Medicinal herbs play a key role in ensuring the health of society due to their therapeutic and preventive properties. Medicinal herbs include to a wide range of plants that are used in the treatment and prevention of various diseases. Culture, laws and regulations, and scientific developments determine the diversity of plants used in different countries. medicinal plants are plants that are used entirely or partly, in fresh, dried, or processed forms, to diagnose, treat, prevent, or maintain the health of people, animals, or other plants [1]. International health entities have paid considerable attention to medicinal plants in recent years. The use of medicinal plants is growing rapidly worldwide [2, 3]. Today, 65–80% of the world’s population use medicinal plant products [1]. In developing countries, about 70% of people prefer to use medicinal plant products as their main source of health care [4, 5]. Given the diversity of plant species, the public culture, and the long history of Iranian traditional medicine, Iranians routinely use medicinal plants to treat and prevent various diseases [6]. According to studies, about 8000 plant species grow in Iran, many of which are considered medicinal species for various reasons. The prevalence of consumption of herbal medicines in different regions of Iran has been reported to be about 19–90% [6, 7]. Evidence suggests that Iranian women are more likely to use medicinal plants and traditional medicine than men [8, 9] and especially Iranian rural women have a relatively high tendency to use medicinal herbs [7].

Numerous theories and models have been developed to assess health-related intentions and behaviors. In this regard, the Theory of Planned Behavior (TPB) is among the most important and valid theories [10]. This theory provides a clear framework for examining the determinants of behavioral intention. Moreover, various tests performed at different spatial and temporal conditions have confirmed high theoretical strength, reliability, and validity of the TPB in predicting consumer behavior in various scientific areas including the use of medicinal plants [11, 12]. Based on the TPB, intention is the most important factor in determining whether or not to perform a particular behavior. In addition, people with more deliberate intentions are more likely to perform a particular behavior. In fact, behavioral intention shows the amount of an individual’s efforts to perform a behavior. This intention is determined by three main constructs including attitude, subjective norms, and perceived behavioral control. Attitude is the degree to which an individual has a desirable or undesirable assessment of a particular behavior. Subjective norms refer to perceived external pressures to display or avoid a particular behavior. These norms reflect people’s willingness/unwillingness to follow others. Perceived behavioral control reflects an individual’s perception of the difficulty of a particular behavior, and the degree to which he/she has control over the behavior. In other words, it refers to an individual’s belief in the adequacy of his/her abilities to perform a particular behavior. People with sufficient opportunities and resources who are confident about their abilities have stronger perceived behavioral control over their tasks. Attitude and subjective norms affect behavior through intention. In addition, perceived behavioral control influences behavior both directly and through intention [10, 13]. According to the TPB, people’s intention to use medicinal plants will not grow stronger unless they believe in valuable properties of these plants. In addition, influential people must encourage them to use medicinal plants, and authorities must provide people with necessary opportunities and resources to process these useful plants.

The TPB has widely been used in predicting health-related behaviors [14], supplementation consumption behaviors [15], and complementary and alternative drugs’ purchase intention [16, 17]; however, the researchers could not find sufficient evidence on factors affecting the use of medicinal plants by rural women in the literature. Therefore, the study used the TPB to identify factors affecting the behavioral intention of rural women to use medicinal plants. The findings are expected to help health care policymakers develop better educational programs and devise detailed plans to promote the use of medicinal plants.

Ajzen [10, 18] suggests that the TPB can be extended and modified by including additional constructs to capture more variance in behavioral intentions. Likewise, in this study, the construct of dissatisfaction with modern medicine is added to the TPB. Dissatisfaction is defined as the “negative affect about outcome unfavourability.” In other words, it signifies the failure to meet an individual’s expectations or needs. In this light, according to the expectation-confirmation theory [19], an individual forms either a positive or a negative affective valuation of an object; depending on such a valuation, he/she subsequently exhibits support behaviors or coping behaviors. Moreover, according to the theory of reasoned action, a positive affect leads to a continuation intention while dissatisfaction is followed by an intention towards discontinuation [10]. In the context of modern medicine, dissatisfaction refers to the degree to which people unfavorably perceive their modern medicine experiences. For instance, modern medicine fatigue and dissatisfaction reflect negative feelings and emotions that users experience when using modern medicine, feelings which could generate push effects on the users’ discontinuous use of modern medicine and make them switch to alternative medicines. Indeed, dissatisfaction with modern medicine has attracted the attention of many researchers, as it seems to influence the intentions of users to switch from modern medicine to alternative medicine. Based on previous studies, dissatisfaction with modern medicine (due to its high costs, the fear of severe side effects, and poor access to concomitantly suitable health care facilities) reinforces people’s tendency to resort to alternative medicine and is one of the main reasons behind the increased use of herbal medicines [20,21,22,23,24]. Especially, the evidence indicates that Iranian rural people tend to use medicinal plants due to their dissatisfaction with modern medicine, which is caused by the low effectiveness of chemical drugs, their side effects and lack of trust in them [25]. In other words, the more dissatisfied people are with modern medicine, its services, and its effects, the greater will likely be their intention to use medicinal plants.

Based on the above discussion, the present study was conducted to examine factors affecting the intentions of Iranian rural women to use medicinal herbs based on the theory of planned behavior (Fig. 1).

Theoretical research model