In our study, the majority of the respondents (97%) were from rural areas. Traditional medicine has a strong following in rural areas because of its remoteness from official health centers. Our findings support previous research that found that the rural community utilized and knew more about medicinal herbs than the urban group [37]. A similar trend was also observed in previous ethnomedicinal studies in Morocco [24, 26, 31].

Concerning sex, both women and men use traditional medicine. However, this use is more common among women (70% vs. 30% for men). This finding supports the view that women are the principal holders of medicinal plant knowledge. In Morocco, very few studies dealing with gender differences in the ethnobotanical knowledge of medicinal plants exist [38, 39]. As is the case for many cultural domains, healing is heavily gendered in Morocco [22, 40, 41] and depends mainly on gendered social roles and experiences [40, 42]. Women are more knowledgeable about the uses of medicinal plants due to the role they play in the process of drying, storing, and preparing recipes for the care of family members at the household level [15]. Therefore, some medicinal plants known only by housewives have been documented in Moroccan rural contexts [43].

Concerning the age of the participants in the survey, 74% of the interviewers were between 30 and 60 years old. Older people (those over the age of 65) account for 24% of the population. Young people (between 20 and 30 years old) represent only 2% of the interviewers. These proportions are indicative of generational differences in knowledge about medicinal plants. Our results indicate that knowledge of medicinal plants is mainly passed orally (80%) (Table 1). Previous studies conducted in Morocco and other Mediterranean countries have reported similar findings with an average age of people practicing traditional phytotherapy often exceeds 50 years [6, 21, 24, 31]. Nevertheless, the vertical transmission of this knowledge between generations is now diminishing. Young people seem to have a weak belief in traditional medicine. It may result from changing lifestyles through modernization and urbanization or the development of modern medicine [9, 10, 37].

Regarding the educational background, 75% of the interviewers were illiterate. The remaining 25% of the informants were divided between primary schooling (11%), informal schooling (8%), and secondary schooling (3%), while 3% of the interviewers had graduate levels. Our results report that illiterate people seem to be more accustomed to using medicinal plants, whereas educated people have very little interest in learning and practicing ethnobotanical knowledge. Other studies in Morocco [24, 27, 29] and abroad have reported a similar tendency [44, 45, 46, 47].

The data compiled during the field studies were analyzed by calculating the use-value (UV) which determines the relative importance of species having more use reports indicated by local informants. During this investigation, 2257 uses were reported. The highest use values were observed by the following species: Marrubium vulgare (UV = 0.57), Salvia rosmarinus (UV = 0.47), Thymus serpyllum (UV = 0.32), Dysphania ambrosioides (UV = 0.29), Eucalyptus globulus (UV = 0.27), Papaver rhoeas (UV = 0.26), Salvia officinalis (UV = 0.24), Urtica dioica (UV = 0.23), Echinops glaberrimus (UV = 0.22), Lavandula angustifolia subsp. angustifolia and Aloysia citrodora (UV = 0.20) (Fig. 2). Species with the highest UV values may have powerful curative properties that can be useful to manage and alleviate a variety of ailments categories. Previous studies from different regions of Morocco have reported the same sort of finding [27, 29, 31]. These species are also prominent in traditional medicine practices in the Mediterranean region [6, 65].

Fig. 2.

Use values of the most used medicinal plants in the Safi Province (Morocco).

It is also important to note that for the abovementioned medicinal plants, many other folk uses have been reported in different regions of Morocco. Furthermore, literature-based proof revealed that these species have proven a wide variety of biological and pharmacological activities (Table 4, Ref. [14, 17, 19, 20, 21, 23, 24, 26, 28, 30, 31, 34, 35, 36, 38, 39, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116]), which may confirm the different popular applications of extracts obtained from these plants in traditional medicine.

FUV indicates the most biologically significant plant family. In the present research, the use-values of families were calculated and are presented in Table 2. The highest FUV was reported for the families Papaveraceae (FUV = 0.26), Urticaceae (FUV = 0.23), Geraniaceae (FUV = 0.17), Oleaceae (FUV = 0.17), Lamiaceae (FUV = 0.17), Myrtaceae (FUV = 0.16), Amaranthaceae (FUV = 0.15), Aristolochiaceae (FUV = 0.15), Asphodelaceae (FUV = 0.14), Verbenaceae (FUV = 0.12), Capparaceae and Rubiaceae (FUV = 0.11) (Fig. 3). Our study indicates that the most important families (Papaveraceae, Urticaceae, Geraniaceae) are monotypic and are represented by only one species in the study area. High values of FUV might be because the plant species are cited by a large number of people in the study area. While the Lamiaceae family was represented by the highest number of plant species (16 taxa).

Fig. 3.

Family use values of medicinal plants used in the Safi Province (Morocco).

In the current investigation, we report the use of different plants’ parts for medical purposes by the local population (Figs. 4,5). Leaves are the part most used (48%), followed by stems (16%), flowers and inflorescence (12%), underground parts (the roots) (11%), and the whole plant (7%). The leaves are easily accessible, which can explain their high use in the medicinal recipe’s preparation. The potential leaves’ curative effectiveness may be due to the higher concentration of bioactive compounds. This finding agrees with most medicinal plant studies in Morocco [29, 23, 24, 28, 31] and neighboring countries [2, 47, 117, 118, 119].

Fig. 4.

Used parts of medicinal plants.

Fig. 5.

Used aerial parts of medicinal plants.

The preparation of recipes from medicinal plants is represented by many methods, such as infusion, decoction, inhalation, and powder. Fig. 6 summarizes the methods of preparation found in this study. The decoction was the most widely used method in the study area for herbal preparation, with a percentage contribution of 42%, followed by infusion, powder, and poultice, which were used in 20%, 18%, and 17% of the preparations, respectively. The remaining 3% was used as inhalation, or “bkhour” (Fig. 6). The higher frequency of decoction use might be related to the simple preparation method. Similarly, the same sort of conclusions has been observed in previous studies [29, 31, 47, 117, 118, 119].

Fig. 6.

Mode of the utilization of medicinal plants.

Fidelity level determines the relative plant’s healing potential. High FL values indicate that a plant is mainly used to treat a single therapeutic category and low FL values show that plants are used for a wide range of diseases. FL is artificially high for plants with few use reports, thus species with less than five use reports were excluded from the discussion. Only 10 plants show high fidelity values to certain diseases category. We report M. vulgare, S. rosmarinus Spenn., T. serpyllum, D. ambrosioides, E. globulus, P. rhoeas, S. officinalis, U. dioica, E. glaberrimus, and A. citriodora as the most important species (Table 4). Concerning gastrointestinal disorders, S. rosmarinus, T. serpyllum, A. citriodora, and S. officinalis have the highest FL values (89%, 77%, 53%, and 50%, respectively). E. globulus is popular in the traditional treatment of respiratory disease (FL = 61%) and M. vulgare for cancer treatment (FL = 44%) (Table 5). Plants with recurrent uses are more likely to be pharmacologically active [120]. Validation of this ethnomedicinal knowledge through in-depth phytochemical and pharmacological studies could be innovative in novel drug research and development approaches.

The distribution of species knowledge concerning the richness of the resources referenced in the examined use category was determined using Rank Order Priority (ROP). As our study showed, the highest ROP values were observed for S. rosmarinus (ROP = 74%), M. vulgare (ROP = 47%), and T. serpyllum (ROP = 44%), indicating that these species are the most well known in the Safi region. While, U. dioica (ROP = 8%), and E. glaberrimus (ROP = 8%) had a lower priority and were considered unpopular among medicinal plants used by the local population.

The ICF measures the agreement between informants and plants used for each disease. Based on the plants’ use reports, we classified the reported ailments into five disease categories (Table 6). Gastrointestinal disorders, respiratory diseases, and anemia have the highest ICF values (85%, 82%, and 66%, respectively), suggesting that these ailments were prevalent in the study area.

The prevalence of gastrointestinal disorders may be due to more common and easily identifiable clinical signs. Among other factors, poor hygienic conditions such as consumption of contaminated food or low drinking water quality may exacerbate digestive troubles in the study area. In the case of respiratory diseases, air quality is a significant risk factor in the development and exacerbation of the disease. Long-term exposure to high levels of pollution, particularly in childhood, raises the risk of developing respiratory disorders [121]. Because the region is home to a large and highly polluting chemical and para-chemical industry, the high ICF recorded for this disease category may explain, at least in part, the high ICF. Anemia received the third-highest ICF value (66%). The majority of cases of anemia are caused by malnutrition or a lack of proper nutrition, which results in iron and other micronutrient deficiencies. In the 2014 Moroccan census, the Safi area had a poverty rate of 10–15% [122]. This fact can explain, at least in part, the prevalence of anemia in this region. Several studies conducted in other areas in Morocco [22, 29, 53, 123], Algeria [47, 54, 124], Pakistan [125], and the Mediterranean region [6] show a similar high prevalence of ICF value for digestive and respiratory diseases.

The UV, first described by Prance et al. [133], represents the relative importance of a species reported locally by taking into account the number of usage reports given by people in the research region. This quantitative index has been frequently used in ethnobotany to determine the species that are most important to specific people. The formula described below was used to calculate it:

(1)$$\mathrm{UV}=\sum \mathrm{Ui}/\mathrm{N}$$

$\sum$Ui is the sum of the total number of use reports concerning a given species and N is the total number of informants interviewed [134]. The most-reported plants have the highest UV values.

To describe the most important plant families in the study area, Family Use Value (FUV) was calculated from the use-values of the species using the following formula [134].

(2)$$\mathrm{FUV}=\sum \mathrm{UV}/\mathrm{N}$$

Where UV is the use-values of the species belonging to the family, and N is the total number of species within each family.

Fidelity levels identify the main use of each plant and calculate the use report’s relative importance for each category of use. The FL was calculated using the following formula based on Friedman et al. [135].

(3)$$\mathrm{FL}(\%)=\mathrm{Np}\times 100/\mathrm{N}$$

Where Np: is the number of use reports for a use category and N is the total number of informants citing the species for the treatment of any use.

RPL is the ratio between the number of ailments treated by a particular plant species and the total number of informants for any disease [129, 130].

ROP is a correction factor derived from FL by multiplying RPL and FL values as explained earlier [131, 132].

(4)$$\mathrm{ROP}=\mathrm{FL}\times \mathrm{RPL}$$

FL is the Fidelity Level and RPL is the Relative Popularity Level.

Informant Consensus Factor highlights plants of particular cultural relevance and assesses the agreement among informants on the plant species used against a disease category as originally proposed by Trotter and Logan [136] and simplified by Heinrich et al. [137]. To use this tool, illnesses were classified [127]. ICF is based on the correlation between an informant’s knowledge and is calculated using the following formula:

(5)$$\mathrm{ICF}=(\text{Nur-Nut})/(\text{Nur-1})$$

Nur is the total number of the use reports in each use category and Nut is the total number of species used in that category.

ICF values lie between “0.00 and 1.00”. A value near 1 indicates that there is a homogeneity of information among informants, while low ICF values indicate that informants do not agree on which plant to use.