The use of herbal medicines to treat various human diseases and ailments has a long, rich history going back centuries. Yet, what is especially striking is the renewed enthusiasm about their therapeutic benefits over the past four decades (WHO, 2023). This resurgence is

visible not only in underdeveloped countries with limited access to modern healthcare facilities, but also in developed nations, where it is driven by a growing awareness among people about their own healthcare needs.

For instance, the United Kingdom, with its long historical tradition in herbal medicine (Nissen, 2010), serves as a model among developed nations, boasting a thriving herbal medicine industry and a centuries-old National Institute of Medical Herbalists. In other European countries and the United States, herbal medicine enjoys significant popularity (Heinrich et al, 2023; https://www.marketdataforecast.com/market-reports/europe-herbal-medicine-market; Calapai, 2008). In the United States, for instance, available data indicate that even as of the early years of the 21st century, about 38% of adults and 12% of children had used some form of traditional medicine (Ernst et al., 2005, Barnes et al., 2008). In 2008, the US National Centre for Complementary and Alternative Medicine reported that herbal therapy or the use of natural products, excluding vitamins and minerals, ranked as the most commonly used alternative medicine (18.9%) (Barnes et al., 2008).

According to a 2012 report from the American Botanical Council, sales of herbal products in the United States exceeded US$5.3 billion in 2011, representing a 4% increase from 2010 (Rashrash et al., 2017, Schultz, 2012). In 2013, there was an 8% increase in sales, reaching a total of US$6 billion (Rashrash et al., 2017, Lindstrom et al., 2014). By 2017, Western herbal medicine represented about 46% of the global herbal medicine market, while Traditional Chinese medicines constituted an additional 36.6% of the market during the same period (Mikulic, 2021).

Among complementary and alternative medicines (CAM), plant-based remedies are the most preferred option for patients seeking alternative treatments for particular medical conditions. According to a 2013 survey involving cancer patients, plant medicine emerged as the most preferred form of CAM. A more recent study conducted in the United Kingdom reported that out of 375 cancer patients surveyed, 127 (34%) had incorporated herbal dietary supplements into their treatment regimen, which included 101 different products (Zahn et al., 2019).

In a 2003 survey conducted in Hong Kong, 40% of the participants expressed a strong preference for Traditional Chinese Medicine (TCM) over Western medicine (Chan et al., 2003). Another study, involving 21,923 adults in the United States, found that 12.8% of the participants had used at least one herbal supplement (Harrison et al., 2004). Qato et al. (2008), also conducted a separate survey in which 42% of the respondents reported taking dietary or nutritional supplements, among which multivitamins and minerals were the most frequently used, followed by saw palmetto, flax, garlic, and Ginkgo. Several recent and past studies have also shown that a significant proportion of the world's population, depends on herbal remedies to address their healthcare needs (Weckerle et al., 2018, WHO, 2023, Ekor, 2014, Bandaranayake, 2006, Bodeker et al., 2005, Mukherjee, 2002). This trend is clearly reflected in the flourishing herbal medicine industry, which now constitutes a substantial segment of the global pharmaceutical sector (Bandaranayake, 2006, Blumenthal et al., 1998, Blumenthal et al., 2000).

Today, herbal medicines are readily accessible in various forms in pharmacies, health food stores, and supermarkets in many parts of the world.

This significant shift in people’s healthcare seeking behaviour, can be attributed to a range of factors, with the foremost being the belief that herbs, being natural, have the potential to promote better health with minimal to no side effects. However, there are several other widely acknowledged contributory factors (Bandaranayake, 2006, Parle and Bansal, 2006, Abbot and Ernst, 1997, Studdert et al., 1998), including:

Claims about the comparative efficacy and safety of plant medicines, especially in treating certain diseases where conventional therapies and medicines have proven ineffective or inadequate.

High cost and potential adverse effects of some orthodox medicines.

Perception that herbal medicines are virtual “cure-alls”.

Increased preference for natural therapies.

Widespread discontent with conventional medical approaches.

Growing tendency towards self-medication.

Patients' reluctance to openly discuss their medical problems with healthcare providers.

Brief duration of doctor-patient consultations.

Patients' readiness and determination to assert their right in making healthcare choices.

Growing tendency to accept or trust anecdotal evidence, often reflected in statements such as "it worked for my friend or relative."

Growing belief in the body's inherent capacity for self-repair.

It is an undeniable fact that the herbal medicine traditions in the United States, Asia, the UK, and various European nations have undergone significant transformation due to a complex interplay of historical, cultural, scientific, and societal factors (Ekor, 2014, Abbot and Ernst, 1997). This evolution has notably led to the increased acceptance and promotion of herbal medicine in these countries, albeit not always fully integrated into their healthcare systems. Moreover, it has played a pivotal role in shaping the development of pharmacopoeias and comprehensive monographs that include standardised dosage recommendations.

In Western herbal medicine, the evolution of herbal medicine dosages can be traced back to the valuable contributions of pioneering herbalists and healers (Ekor, 2014, Abbot and Ernst, 1997). Notably, in the United States, the Eclectic physicians, and in the United Kingdom, the British Herbal Pharmacopoeia (BHP), played crucial roles by providing comprehensive guidelines for various herbal preparations (Bone, 2003, Bone and Mills, 2013). This significant development enabled practitioners to prescribe herbal medicines with a primary focus on minimising potential risks of toxicity and adverse effects.

Similarly, within traditional Asian medicine systems such as Traditional Chinese Medicine (TCM) and Ayurveda, the development of herbal medicine dosages emerged as integral components of their holistic healing methodologies (Bone, 2003, Bone and Mills, 2013, Ekor, 2014, Abbot and Ernst, 1997). These traditional medicine systems skillfully harmonise energetic principles with empirical evidence, forming a robust framework for the prudent administration of herbal remedies.

In contrast to the progress seen in Europe, Asia, and the United States, African herbal medicine lacks universally accepted dosage guidelines (Ekor, 2014, Fokunang et al., 2011), highlighting an important global disparity. This gap raises valid concerns about the quality, safety, and efficacy of African herbal remedies.

This paper seeks to provide an overview of the historical development of standardised dosages in European, Asian, and US herbal medicine systems (Ekor, 2014, Abbot and Ernst, 1997, Bone, 2003, Bone and Mills, 2013). It also highlights the complex factors contributing to the absence of standardised dosages in African herbal medicine, drawing attention to the global disparities in this regard. In addition, the paper presents a multidimensional approach for addressing these vital issues, with the aim of fostering a more uniform and safer landscape for herbal medicine practices worldwide.

In Western herbal medicine, the varying dosage approaches is usually broadly categorised into two main schools of thought: the high-dosage and low-dosage paradigms. While one group asserts that a plant's therapeutic efficacy is linked to a precise concentration of its bioactive compounds, the opposing viewpoint places greater importance on the plant's inherent energy or vital force over the sheer quantity of the actual herb used (Bone, 2003, Bone and Mills, 2013).

Adding another dimension to these two schools of thought is the belief that the pharmacological quantities of a plant's active components primarily act as catalysts to promote the restoration of health and overall well-being (Bone, 2003, Bone and Mills, 2013).

These differing viewpoints highlight the necessity for a standardised dosage framework to address potential ambiguities and foster patient confidence. Such a comprehensive framework should encompass the diverse array of established historical and contemporary dosage methodologies, drawing upon the wealth of experience from different herbal medicine traditions.

Notable examples of these standardised dosage protocols can be found in various traditions, including Western herbal medicine (Niemeyer et al., 2013, Bone and Mills, 2013), Traditional Chinese Medicine, and India's Ayurveda (Patwardhan et al., 2005). Additionally, they are based on pharmacopoeia standards, pharmacological research, and clinical studies (Niemeyer et al., 2013), forming a global variety of approaches aimed at ensuring the safety and efficacy of herbal remedies.

Across Europe and the United States, the development of herbal medicine dosages has been a gradual process spanning centuries, shaped by a blend of empirical observations, traditional knowledge, and scientific advancements (Niemeyer et al., 2013). In ancient Europe for instance, herbal medicine was deeply intertwined with folklore, mysticism, and spirituality. Determining dosages often involved a process of trial and error, guided by long-established traditions and the expertise of healers (Petrovska, 2012, Fokunang et al., 2011). Although early herbal texts such as Dioscorides' "De Materia Medica" offered valuable insights into herbal remedies and their potential applications, precise dosages were often left undefined (Clair, 2019).

During the Renaissance, there was a significant resurgence of interest in the natural sciences, and herbalists such as Nicholas Culpeper sought to make knowledge of herbal medicines more accessible through his "Culpeper's Herbal." However, even amid this revived interest in herbalism, the tradition persisted in combining empirical methods with folk wisdom. Throughout this period, dosage recommendations were often imprecise, relying on terms such as "a handful" or "a pinch" rather than standardised measurements (Leong, 2014, Bennett, 2008).

At the same time, pioneers such as Paracelsus conducted experiments involving plant extracts and distillations, laying the foundation for the extraction of active compounds from plants (Abubakar and Haque, 2020, Leong, 2014, Bennett, 2008). The 19th century witnessed a noticeable transition toward a more systematic approach to herbal medicine. Medical herbalists such as Samuel Thomson and John King recommended specific dosages and formulations, drawing from their clinical expertise and observations (Flannery, 2002, Denham, 2013).

In response to the shortcomings of mainstream medicine during that period, the Eclectics, a group of American physicians, adopted a unique medical approach. They combined traditional European herbalism with Native American herbal practices and developed specific herbal dosages based on their understanding of physiology. At the core of their philosophy was the belief in using plant medicines to restore the body's balance and vitality, and they diligently compiled a “materia medica” that included precise dosage recommendations for a wide range of herbs.

The Eclectics adopted a holistic approach to health, treating not only the physical symptoms of illness but also the emotional, mental, and spiritual well-being of the individual. They were noted for administering larger quantities of remedies derived from fluid extracts, departing from the dosages recommended in contemporary reference texts and pharmacopoeias. As illustrated in the table below, significant similarities existed between the dosages prescribed by the Eclectics and those recommended in established texts (Bone and Mills, 2013, Puchalski, 2001).

The experience of Europe and the United States, serves as a compelling example of the significance of having a standardised dosage framework that harmonises the wisdom of the past with contemporary scientific rigour. As herbal medicine continues its transformation, and becomes integrated into modern healthcare systems worldwide, understanding these diverse dosage paradigms offers valuable insights for practitioners and researchers.

The British Herbal Pharmacopoeia (BHP), initially published in the early 20th century in the United Kingdom, made a significant contribution to herbal medicine. It provided a standardised and authoritative reference for the preparation, dosages, and therapeutic applications of herbal medicines. The BHP played a pivotal role in introducing consistency and credibility to herbal medicine, helping practitioners and manufacturers in formulating herbal remedies with reliable dosage recommendations (Bone and Mills, 2013, British herbal pharmacopoeia, 1983), which were derived from a synthesis of traditional use, historical records, clinical observations, and contemporary scientific research.

The BHP of 1983 served as a valuable reference for those seeking evidence-based information on herbal preparations. However, there were noticeable inconsistencies in the dosages specified in the BHP 1983, as illustrated in the table below (Bone and Mills, 2013, British herbal pharmacopoeia, 1983). These variations are particularly evident when comparing the dosages for specific tinctures with their corresponding liquid extracts. For example, in the case of a 1:5 tincture of a specific herb, one might expect the dose range to be five times that of a 1:1 liquid extract, but this is not always the case, as exemplified by Agrimonia eupatoria L. (Bone and Mills, 2013, British herbal pharmacopoeia, 1983) in the table below.

The inconsistency in dosages presented in the BHP 1983 could be attributed to two main factors (Bone and Mills, 2013):

The recommended dosages in the BHP 1983 probably reflects the different philosophies between herbal practitioners, who used extracts and those who preferred tinctures.

The methods used for preparing tinctures and 1:1 fluid extracts are significantly different. Typically, fluid extracts are prepared by reconstituting more concentrated extracts rather than the traditional method of reserved percolation. As a result, the heat or vacuum used, can lead to the degradation of active components. On the other hand, tinctures are prepared without heat or a concentration method, resulting in better preservation of the plant parts and their constituents. Also, because the production of fluid extracts often involved the use of lower alcohol strengths compared to tinctures, incomplete extraction of vital active components from the original plant material may have occurred. Consequently, the activity of a 1:1 fluid extract can vary significantly from that of a 1:5 tincture (Bone and Mills, 2013, British herbal pharmacopoeia, 1983).

The low-dosage approach in herbal medicine, involves the use of diluted tinctures or drop doses for therapeutic purposes. This approach is rooted in the belief that introducing herbal remedies gradually and gently can yield therapeutic benefits while minimising the risk of potential side effects. It is consistent with a holistic healing perspective, which recognises the body's innate capacity to restore balance. Practitioners who embraced this approach prioritised gentleness, personalised treatment, and trust in the body's natural healing mechanisms.

Currently, the preference for drop dosages, often using 1:5 tinctures or stronger, is prevalent among practitioners in the United States, New Zealand, certain regions of Europe (especially within the homeopathic community), and to some extent, Australia. In Europe, this approach is notably prominent among homeopaths who use combinations of herbal mother tinctures, a practice that is occasionally inaccurately referred to as 'phytotherapy' (Bone and Mills, 2013, British herbal pharmacopoeia, 1983).

Indeed, the historical connection between the low-dose approach in herbal medicine and the evolution of Eclectic medicine in the United States is both fascinating and significant. The introduction of the concept of 'specific medication' in 1869 by John Scudder, marked a departure from some of the conventional medical practices of his era and shared certain similarities with other holistic healing paradigms. With this concept, medicines were carefully tailored to the symptom profile of each patient and administered in the smallest effective doses. While this might suggest comparisons to homeopathy, there were significant differences. Scudder used material doses, albeit smaller than those employed by other Eclectic physicians, and his prescriptions were not based on the "law of similars." However, similar to classical homeopathy, the tendency was to use only one medicine at a time. Initially, Scudder advocated for 'specific medicines' in the form of tinctures made from fresh plants. The term 'specific tincture' is still occasionally used to describe a tincture made from fresh plants. Consequently, the practice of using drop doses of tinctures, particularly those derived from fresh plants, can be traced back to Scudder's influential contributions (Felter, 1912, Bone and Mills, 2013, British herbal pharmacopoeia, 1983).

Scudder's emphasis on individualised treatment and the use of specific medications had a lasting impact on Eclectic medicine, and to a certain extent, influenced the broader evolution of herbal medicine practices in the United States. His ideas contributed to the development of an approach that resonated with the individualized and holistic philosophy of holistic healing and integrative medicine (Felter, 1912).

Building on John Scudder's concept of specific medication, another influential Eclectic physician, John Lloyd, introduced modifications to this approach. Lloyd believed that drop doses of tinctures were of low concentration and potency. As a result, he pioneered the development of concentrated, semi-purified liquid herbal preparations known as 'specific medicines.' These specific medicines were prepared using intricate and often secretive techniques, involving solvents other than ethanol and water. Lloyd's objective was to eliminate colourants and inert substances, departing from conventional practices, while preserving the herb's chemical complexity. These concentrated preparations were widely recognised as being stronger than traditional 1:5 tinctures and were typically administered in the form of drop doses (Flannery, 1996, Bone and Mills, 2013; BHP, 1983).

Lloyd's specific medicines rapidly gained widespread acclaim among the community of Eclectic physicians due to their remarkable strength and perceived effectiveness. These preparations provided practitioners with more robust and concentrated options for tailoring treatments to individual patients. However, the relatively high cost associated with importing Lloyd's specific medicines spurred the development of simpler herbal formulations in England, which were more consistent with the practices of American physiomedicalists. In their clinical approaches, Eclectic physicians often prescribed Lloyd's specific medicines in relatively higher doses, typically about 60 drops (3 mL), three times daily. This significant dosage regimen underscored their strong belief in the efficacy and therapeutic potential of Lloyd's concentrated preparations (Flannery, 1996).

The historical transformations in herbal medicine practices in the United Kingdom, especially concerning the use of different herbal preparations and dosage regimens, illustrate the continuous evolution and adaptability of the field. Historically, herbalists in the United Kingdom heavily relied on fluid extracts, often prepared using heat or concentration methods. However, during the 1980s, concerns expressed by a new generation of herbal practitioners about the quality and consistency of these fluid extracts, led to a re-evaluation of herbal preparation techniques.

In response to these concerns, newer practitioners in the United Kingdom moved towards using 1:5 tinctures, which involve mixing 1 part of the herb with 5 parts of the extracting solvent, typically a combination of alcohol and water (Flannery, 1996, Felter, 1912, Bone and Mills, 2013, British herbal pharmacopoeia, 1983).

Tincture formulations are typically recommended at doses of 2.5 to 5 mL, taken three times daily. However, achieving the BHP 1983 recommended doses for tinctures using this approach is only possible when the formulation contains one to three herbs. Practitioners often do not strictly adhere to this restriction (Flannery, 1996, Felter, 1912, Bone and Mills, 2013; BHP, 1983).

Generally, herbs are not prescribed individually; instead, they are combined into formulas. These formulations are prepared based on a practitioner's practical experience, an understanding of the herbal medicine traditions of the region, knowledge of the phytopharmacology of the active compounds found in individual herbs, and the specific presenting complaint of the patient. For instance, in the United Kingdom, a prescription aimed at managing digestive health might be composed of herbs such as angelica root (Angelica archangelica L.), dandelion root (Taraxacum officinale L.), peppermint leaves (Mentha x piperita L.), chamomile flowers (Matricaria chamomilla L.), and gentian root (Gentiana lutea L.).

Tinctures of each of these individual herbs will be blended together in appropriate proportions, and administered to the patient at a dose of 5 mL three times a day.

Commission E and the European Scientific Cooperative on Phytotherapy (ESCOP) monographs have played pivotal roles in establishing dosage guidelines for European herbal medicines through evidence-based recommendations (Blumenthal et al., 2000, Klein et al., 1998, ESCOP Monographs, 2004).

Commission E, a regulatory body in Germany, consisted of experts from diverse fields, including medical professionals, pharmacologists, pharmacognocists, and toxicologists drawn from academia and industry. It was established under the auspices of the German Health Department with the primary objective of evaluating the safety and efficacy of herbal medicines.

Commission E compiled an extensive collection of monographs covering a wide range of medicinal plants. These monographs provided comprehensive information on the plants' applications, methods of preparation, and recommended dosages, based on a combination of scientific research, clinical trials, and traditional knowledge. Notably, a significant portion of these recommendations focused on infusions or decoctions, which reflected the prevalent practice of consuming herbal teas in Germany.

In Germany, herbal medicines could only obtain approval for product registration if they received a positive monograph from Commission E. The recommended daily doses generally ranged from 2 to 10 g. However, in certain cases, monographs specified dosages for a particular herb based on its primary active constituents. For example, the monograph for Ephedra specified a daily dosage of 45 to 90 mg of alkaloids, which is equivalent to about 4 to 8 g of the herb. Nevertheless, similar to the BHP 1983, there were instances where the recommended doses for tinctures and extracts provided by Commission E did not consistently correlate. For instance, while the single-dose recommendation for valerian tincture was 1 to 3 mL, the suggested dose for its fluid extract was 2 to 3 mL (Bone and Mills, 2013, British herbal pharmacopoeia, 1983).

The European Scientific Cooperative on Phytotherapy (ESCOP) represents a collaborative effort among European herbal medicine experts. ESCOP has also produced a series of monographs that provide comprehensive information on the therapeutic applications and recommended dosages for various herbal remedies. Similar to Commission E, these monographs are based on scientific research, clinical trials, and traditional knowledge, making them a highly regarded resource among healthcare professionals and regulatory bodies. The ESCOP monographs have contributed significantly in advancing the standardisation of herbal medicine dosages throughout Europe, thereby ensuring consistent, evidence-based approaches to herbal therapy.

Despite the historical influence of Western medicine on Hong Kong, China, and Taiwan, China, Traditional Chinese medicine (TCM) remains deeply-rooted in these areas, as well as in Japan and South Korea. In a 2010 opinion survey, it was reported that 75% of residents in Hong Kong, China, sought TCM therapy, with 20% regularly consulting TCM doctors. Similarly, Taiwan, China, has a rich tradition of depending on TCM as a trusted form of healthcare. The transmission of TCM to Korea dates back to the 2nd century AD when communication channels were established between China and Korea. Over time, TCM evolved into Korean medicine. As of 2012, South Korea had 12,639 KM hospitals and 20,668 licensed physicians (Chen et al., 2015).

In TCM, dosages are determined with the aim of restoring balance and harmony within the body. Practitioners place great emphasis on carefully evaluating how physical, emotional, and energetic factors interact. TCM prescriptions, therefore, take into account an individual’s distinct constitution, the presenting complaint, and the specific herbs to be used. This tailored approach implies that what might be effective for one person may not necessarily be suitable for another, even if their health conditions are similar.

TCM often uses a combination of various herbs within a single formula, aiming to harness their synergistic effects. Consequently, dosages are carefully adjusted to ensure a harmonious interaction among the diverse herbal components. TCM offers a variety of dosage forms, including decoctions, powders, pills, and tablets. Each of these dosage forms is accompanied by its own unique dosage considerations, which take into account factors such as the patient's weight, age, severity or acuteness of their condition, strength of the herbs involved, intended duration of treatment, and the chosen route of administration.

Given the poor solubility of certain plant constituents in water, TCM dosages generally tend to be relatively higher, typically ranging from 3 to 9 g, administered three times daily, especially for decoctions. Conversely, TCM preparations in the form of pills or powders may involve lower doses compared to decoctions. When a single herb is used in isolation or in combination with just a few others, a larger dosage may be recommended, compared to when it is part of a more extensive formula (Zhu, 2022, Zhou et al., 2021, Lin et al., 2023).

In modern TCM practice, there is a growing trend among practitioners to prescribe granulated formulas. These formulas are prepared by dehydrating or freeze-drying decoctions of a herbal combination. As a standard, a prescription of 2 g of granules is given three times a day, which is equivalent to 6 to 10 g of the original dried herbs per dose.

The table below provides a comparison of dosages for some herbs or closely related species, which are used in both Chinese and Western herbal medicine.

An interesting observation from this table is the remarkable similarity in the dosage range between some Western herbal medicine preparations and that of TCM, despite some notable differences. For example, in TCM, Astragalus membranaceus Fisch (Huang Qi) is often used in larger doses, typically ranging from 9 to 30 g per day, as it is considered a tonic herb for strengthening the body's vital energy (Qi). Conversely, in Western herbal medicine, Astragalus is generally used in lower doses, often as an extract or capsule, with recommended doses typically ranging from 500 mg to 3 g per day. Similarly for Ephedra sinica Stapf (Ma Huang), TCM may use it in higher doses, typically between 3 to 9 g per day when prepared as a decoction. But in Western herbal medicine, Ma Huang is prescribed with caution due to its ephedrine content, and its use has been restricted or regulated (Zhang et al., 2018). It is typically not used in the same way as in TCM, and dosages, if recommended at all, would be much lower.

In a manner similar to Western herbal medicine, TCM also uses herbal formulations, which often comprise a mixture of various herbs carefully combined in precise proportions. These herbs are categorised into four distinct roles within the formula: the chief (providing the primary therapeutic effect), deputy (offering supportive functions), assistant (reinforcing the treatment), and the envoy (guiding and harmonizing the formula's actions) (Marshall, 2020).

One example of a TCM formula is "Xiao Yao San," also known as "Free and Easy Wanderer" or "Rambling Powder." This formula is composed of:

Chai Hu (Bupleurum chinense DC) - 9 g

Dang Gui (Angelica sinensis (Oliv.) Diels) – 9 g

Bai Shao (Paeonia lactiflora Pall.) - 9 g

Bai Zhu (Atractylodes macrocephala Koidz) - 9 g

Fu Ling (Poria cocos Schw) - 9 g

Zhi Gan Cao (Glycyrrhiza uralensis Fisch) - 6 g

Bo He (Mentha haplocalyx Briq) - 3 g

(Yeung et al., 2015, Yeung et al., 2012).

All the above herbs are combined, and boiled in water to make a tea-like decoction.

This particular formula is commonly used to treat conditions related to stagnation of liver qi and spleen deficiency. Such conditions often present with symptoms such as irritability, mood swings, abdominal discomfort, and irregular menstruation in women.

In Ayurveda, dosages are determined based on an individual's constitution, known as "Prakriti", the nature of the imbalance they are experiencing, referred to as "Vikriti" (Huang et al., 2022), the specific herbs or formulations to be used, and the intended therapeutic outcomes. Like all the established herbal medicine traditions, Ayurveda places strong emphasis on a personalized approach to dosages, with attention given to the unique circumstances of each individual. Dosages are precisely tailored to a person's "dosha," signifying the fundamental energies or functional principles governing the body, mind, and soul (Hankey, 2001). This approach is dedicated to preserving harmony and balance in all aspects of one's well-being.

Just like Western herbal medicine and TCM, Ayurveda formulations commonly contain a variety of herbs. Nevertheless, Ayurveda formulas tend to exhibit a greater degree of complexity and, unlike Western herbal formulas, may include minerals as essential components.

An example is the formula, Mahasudarshan Churna used for immune support, and the treatment of diabetes, chronic fever and loss of appetite.

Chirayata (Swertia chirata Buch.-Ham. ex Wall.)

Kutki (Picrorhiza kurroa Royle ex Benth)

Haritaki (Terminalia chebula Retz)

Bibhitaki (Terminalia bellerica (Gaertn.) Roxb.)

Amla (Emblica officinalis Gaertn.)

Guduchi (Tinospora cordifolia (Wild.) Miers)

Trikatu (consists of black pepper, ginger, and long pepper)

Neem (Azadirachta indica A. Juss.)

Daruharidra (Berberis aristata DC)

Musta (Cyperus rotundus L.)

Vasa (Adhatoda vasica L.)

Tulsi (Ocimum sanctum L.)

Pippali (Piper longum L.)

Haldi (Curcuma longa L.)

Bhringraj (Eclipta alba L.)

(Sharma et al., 2019).

To provide general immune support and treat mild fever, the recommended dosage is typically 1-2 teaspoons, equivalent to about 3-6 g. This would be mixed with warm water or honey and taken twice a day. But for specific health concerns or under the guidance of an Ayurvedic practitioner, both the dosage and duration of use may be adjusted accordingly.

(Sharma et al., 2019).

In Ayurveda, dosages are carefully adjusted to achieve a harmonious balance among the properties of the herbs found within a specific formulation. Ayurveda employs a wide array of dosage forms, including powders, decoctions, oils, and pastes. In contrast to TCM, Ayurveda has a diverse range of dosage options, reflecting the intricate nature of the formulations, which are meticulously prepared over several days. For herbs considered "individually safe," Ayurveda dosages typically range from 1 to 6 g per day, commonly administered in the form of powders and tinctures. For decoctions, higher dosages are often recommended (Ghosh et al., 2018, Arun et al., 2014).

The clinical trial approach remains the most widely accepted method for determining effective doses of single herbs or herbal formulations. Although clinical trials may not always give precise optimal doses, they provide a degree of confidence in clinical outcomes. These trials are essential for assessing the effectiveness of herbal medicines at various dosage levels, enabling a comparative analysis of outcomes against a placebo. This approach helps in determining the optimal dosage required to achieve desired therapeutic effects, indicating that at a specific dose of a particular preparation, a certain percentage of patients are likely to exhibit a positive response. For instance, the oral administration of a standardized Ginkgo biloba L. extract at a dose of 120 mg per day, equivalent to about 6 g of dried leaves, over a two-month period has been found to improve intermittent claudication in about 60% of patients (Mei et al., 2017, Nicolaï et al., 2013).

Furthermore, clinical trials play a crucial role in assessing potential side effects and adverse reactions associated with different dosage regimens, thereby providing valuable information for healthcare practitioners and regulatory agencies. Given that herbal medicine dosages can vary based on factors such as age, gender, and overall health, clinical trials help in establishing appropriate dosage guidelines for specific demographic groups, enabling more personalised and effective treatment plans. Moreover, clinical trials play a crucial role in standardizing herbal medicine formulations by establishing consistent practices and dosages. This ensures the replicability of results and facilitates cross-study comparisons.

In specific cases, trials may involve the use of standardised extracts, which can be correlated to the effects of the whole herb. A notable example is the administration of silymarin in liver disorders at a daily dosage of 240 mg, corresponding to 8 to 16 g of Silybum marianum (L.) Gaertn. seeds (Bones and Mills, 2013).

However, application of the clinical trial approach in herbal medicine has limitations due to the highly personalized nature of prescriptions, often tailored to the unique circumstances of individual patients (Parveen et al., 2015, Bone and Mills, 2013). The complexity of herbal mixtures, influenced by factors such as plant species, geographic location, and cultivation methods, poses a significant challenge in standardising dosages across different herbal products. The absence of standardised methods for preparing and administering herbal medicines can result in dosage variability, and affect the reliability of trial results.

In addition, due to the resource-intensive nature of clinical trials, obtaining funding for such studies can be challenging, impeding the conduct of large-scale, well-designed trials. Additionally, cultural and ethical considerations specific to herbal medicine research, obtaining informed consent, ensuring participant safety, and determining the long-term effects and optimal duration of herbal medicine use that require extended follow-up periods, also present unique challenges.

In effect, while clinical trials are indispensable for determining herbal medicine dosages, addressing the unique challenges associated with herbal products is crucial for advancing evidence-based practice and ensuring the safe and effective use of these traditional remedies.

In contrast to the well-established herbal medicine dosage regimens observed in Europe, the United States, China and India, Africa presents unique circumstances that have led to the absence of standardised dosages for its herbal medicines. African traditional medicine, is characterised by a complex interplay of historical, cultural, and socio-economic factors that have shaped the use of herbal remedies in many countries.

Across the vast expanse of the African continent, from the lush rainforests to the arid savannas, herbs are revered and harnessed for their therapeutic properties. For many communities, the lush landscapes are not only sources of sustenance, but also serve as a treasure trove of plants forming an extensive pharmacopoeia. Local communities have developed a profound understanding of these plants, carefully selecting them for specific purposes. The knowledge of choosing the right herbs, harvesting them at optimal times, and preparing them has been traditionally transmitted across generations, primarily through oral traditions. Elders and healers take on the crucial role of safeguarding and passing down this invaluable heritage.

However, despite the significant surge in research activities on African herbal medicines, the primary focus is often on conducting pharmacological and phytochemical studies, rather than formulating specific remedies or establishing standardised dosages. This situation has sparked a broader discussion about the future direction of African herbal medicine within the global healthcare landscape (Ozioma and Chinwe, 2019, Fokunang et al., 2011).

The task of establishing standardised dosages to ensure the safe and effective use of African herbal medicines is beset with multifaceted and distinctive set of challenges. Among these challenges are:

Influence of different cultural practices, diverse range of medicinal plants, and varying preparation methods, with each region, tribe, or family having its own unique dosage recommendations, often based on factors such as the type and severity of the illness, the patient's age and constitution, and the availability of specific ingredients.

Dependence on traditional knowledge, with dosages often derived solely from empirical knowledge, rather than through rigorous clinical trials and dose-response studies.

Lack of research on dosages and limited data on the safety profiles of specific herbal remedies.

Lack of enforceable regulatory controls to guide dosage standardisation.

In light of these challenges, there have been calls for African governments to allocate resources to conduct clinical trials and dose-response studies. Conversely, a less-discussed and speculative suggestion relates to the possibility of extrapolating dosages for African medicinal plants from the dosage guidelines for similar plant species found in well-documented sources such as the BHP 1983, WHO (2006), and the ESCOP monographs (2004). This intriguing proposal, while seemingly reasonable, remains largely unreported in the literature. Yet, the idea of matching dosages for African herbal medicines and those from other regions carries significant flaws stemming from the inherent complexities of medicinal plants. One of the fundamental problems of this suggestion is the assumption that similarities in the physical appearance of plant species, automatically translate into shared constituents and therapeutic effects. This oversimplification overlooks the intricate biochemical diversity inherent in plant species, even when their visual characteristics may appear similar.

Moreover, besides their physical attributes, plants are also characterised by their complex chemical compositions. Even plants belonging to the same genus or species can exhibit significant variations in the types and concentrations of bioactive compounds they contain. These distinctions are influenced by factors such as geographic location, climate, soil, and growing conditions. As a result, two visually identical plants may, in reality, possess vastly different therapeutic properties.

Given that the therapeutic effects of a herb depend on the intricate synergy among multiple compounds within it, even slight disparities in the levels of a single compound can upset this delicate balance. This disruption has the potential to diminish the herb's efficacy or trigger adverse reactions. Therefore, it is important to recognise that the efficacy and safety of a particular plant at a given dosage in one region, cannot be automatically extrapolated to a visually similar plant in another region.

African traditional medicine is intricately intertwined with culture, spirituality, and local customs. The determination of suitable dosages for a herb in this context, does not rely solely on the physical attributes and chemical components of the plants, but also incorporates the broader cultural and contextual factors in which they are employed. Blindly adopting dosages from other regions can inadvertently undermine the cultural and traditional elements that are integral to the identity of African herbal medicine.

Furthermore, it is worth noting that many African medicinal plants have not undergone the same level of scientific scrutiny as their counterparts from other regions. Scientific research is crucial for identifying active compounds, establishing safety profiles, and validating traditional uses. Unfortunately, there is a paucity of comparative research that directly assesses the pharmacological properties and dosages of African medicinal plants in contrast to those from other regions.

Determining appropriate dosages must also take into account the considerable variations in individual responses to treatment. Factors such as genetics, metabolism, and overall health status exert significant influence over how an individual's body processes and reacts to herbal remedies. These responses can vary significantly among individuals and different populations. Consequently, what may constitute an effective dose for one person, might prove inadequate or excessive for another. Thus, responses to the same dosage can differ not only between African populations and those from other regions but also within diverse groups due to disparities in genetic makeup, physiological traits, and lifestyle choices. As a result, herbal medicine dosages should be tailored to the unique biochemical and physiological characteristics of the specific target population.

In light of the foregoing, in developing dosages for any medicinal application, the paramount focus should be on prioritising safety. Achieving this goal requires reliable documentation, culturally sensitive research practices, and a regulatory framework that truly understands the real ethos of herbal medicine.

To address these challenges effectively, a holistic approach is essential—one that effectively bridges traditional knowledge with advanced scientific methodologies. This multifaceted approach encompasses the following key elements:

Leveraging cutting-edge scientific research methods to identify the key bioactive compounds responsible for a plant's therapeutic effects. These findings can be correlated with observed therapeutic outcomes to establish dosage ranges that align with the concentrations of these bioactive compounds.

Conducting well-designed clinical trials involving a diverse range of individuals, reflecting the heterogeneity of the African population.

Leveraging the emerging field of pharmacogenetics to investigate how individual genetic variations influence responses to these medicines, in order to customise dosages for each person in accordance with their genetic profiles.

Facilitating collaborative research that brings together traditional medicine practitioners, scientists, and health experts. This collaborative effort should aim to develop dosage guidelines that harmonise the ethnomedical knowledge of local communities with contemporary medical standards.

Advocating for an effective regulatory framework, in collaboration with policymakers, healthcare institutions, and traditional medicine practitioners, based on scientific and ethnomedical evidence.