Ethnobotanical plant species in the study areas

A total of 164 medicinal plant species belonging to 60 families and 140 genera were collected and documented for their use in treating 83 ailments in humans and livestock. The number of medicinal plant species identified in this study is notably higher compared to similar research conducted in various regions of Ethiopia. For instance, a study by [30] reported 81 medicinal plant species in the Guraferda District of the Benchi-Sheko zone, Southwest Ethiopia, while [31] documented 128 species in the Quara district of northwestern Ethiopia. Other studies, such as those by [55] and [56], identified 48 and 49 species, respectively, in the Madda Walabu District of Bale Zone and Ghimbi District in Southwest Ethiopia. In contrast, studies from other parts of the world have reported only 42 to 55 medicinal plant species, as noted by [57, 58]. However, reports by [41, 59] identified 266 and 189 species, respectively, which surpasses the findings of the current study. The relatively high diversity of traditional medicinal plant species in this area may be attributed to the varied landforms, favorable climatic conditions, and the rich indigenous knowledge within the community that aids in the protection of plant biodiversity. It has been observed that communities with valuable indigenous knowledge tend to conserve their medicinal plants effectively, as highlighted by [60], who noted that local populations possess accumulated knowledge for classifying, utilizing, managing, and conserving natural resources. In this study, the majority of medicinal plants belonged to the families Asteraceae, Fabaceae, Lamiaceae, Cucurbitaceae, Poaceae, Solanaceae, and Euphorbiaceae, with respective species counts of 14, 14, 10, 8, 8, 7, and 7. Other families had fewer species represented. This finding aligns with previous literature that also indicates a high abundance of Asteraceae, Fabaceae, Lamiaceae, and Cucurbitaceae families [23, 24, 41, 35, 52]. Among the 164 medicinal plants identified, 111 (67.68%) were used to treat human ailments, 32 (19.51%) were utilized for livestock ailments, and the remaining 21 (12.80%) were effective for both. This indicates a greater focus on treating human diseases compared to livestock. Various ethnobotanical studies conducted by different researchers over the years have similarly shown that most medicinal plants are primarily used for human ailments [24, 30, 40–61].

Habitats and growth forms of medicinal plant

In this study, a significant number of medicinal plant species were collected from various habitats in the study area. The majority (49.39%) were sourced from wild areas, followed by home gardens (21.34%), agricultural fields (14.04%), life fences (9.14%), and roadsides (6.09%). Field observations revealed that wild areas harbored a rich diversity of medicinal plants, highlighting their importance as a primary source of plant biodiversity for medicinal purposes. Conversely, fewer medicinal plants were found along roadsides and in life fences. The roadside plants faced greater exposure to various threats, while those in life fences were limited in number, as they were primarily planted by farmers for fencing and other purposes. Although the number of medicinal plants in home gardens was smaller than in wild areas, these plants were well-conserved and protected by traditional practitioners of medicine, who cultivated and managed them effectively. Informants noted that wild areas were increasingly threatened by factors such as rapid population growth, house construction, overgrazing, and unmanaged collection of charcoal and firewood. Previous studies ([30, 55, 53, 62]) have similarly reported that most medicinal plants are found in wild settings, which are often exposed to various threats. The study identified different growth forms of plants, each utilized to varying degrees. Herbs constituted the largest proportion at 46.34%, followed by trees (25.60%), shrubs (20.73%), and climbers (5.48%). Among the herbs collected, 34.14% were used to treat human ailments, 7.92% for livestock ailments, and 4.26% for both. This indicates that herbs are the most commonly used medicinal plants in the area, followed by trees. The predominance of herbs can be attributed to their adaptability; they thrive in the shade of larger trees and grow rapidly, allowing for quick reproduction. Herbs were collected from wild areas, home gardens, agricultural fields, life fences, and roadsides, demonstrating their adaptability to various habitats. While previous studies in Ethiopia [23, 31, 42–64] have reported a high prevalence of herbs and shrubs for medicinal uses, this study found that trees ranked as the second most dominant group after herbs, which may reflect the unique plant biodiversity of the current study area compared to others. In contrast, many studies have highlighted the use of shrubs and trees at both local [31, 53, 37] and global scales [65–68]. This trend may be due to their consistent annual availability and resilience to drought conditions and invasive species, making them suitable for widespread use in traditional medicine.

Plants parts used for medicine and mode of preparation

Healers in the study area utilize various parts of plants for their medicinal properties. In this research, leaves were the most frequently cited plant part used for medicine preparation, accounting for 72 instances (43.9%), followed by roots at 49 instances (29.87%), bark and seeds at 20 instances (12.19%), stems and bulbs at 7 instances (4.26%), fruits at 12 instances (6.55%), and flowers at 2 instances (1.21%). This indicates that healers in the area predominantly collect leaves for medicinal purposes over other plant parts. Traditional medicinal practitioners in the region prefer leaves due to their high healing potential, freshness, nutrient content, and ease of collection. However, since leaves are vital for the plant's food production, excessive harvesting can lead to the destruction of the entire plant, a concern that traditional practitioners do not seem to acknowledge. Similar findings have been reported by other studies [23, 47–70] and in various countries [68, 71–74], which suggest that leaf harvesting poses a threat to the sustainability of medicinal plants. The removal of leaves can hinder vegetative growth and reproductive development, such as flower production and seed set, ultimately limiting the natural regeneration of these plants. According to [30], herbal preparations involving roots, rhizomes, bulbs, barks, stems, or whole plant parts can negatively impact the survival of the parent plants. Roots were the second most commonly used plant part for medicinal purposes. Being underground, roots have better access to water and minerals, keeping them fresh and less susceptible to drying out compared to other parts of the plant. They also possess significant healing potential similar to that of leaves. However, harvesting roots requires digging them out of the soil and separating them from other plant parts, which can disrupt water transportation within the plant. Consequently, plants with harvested roots face a higher risk of damage and loss within their communities. Literature from various authors supports these findings, indicating that leaves and roots are the primary plant parts used for medicinal purposes [41, 44, 75]. Herbalists in the study area employ different preparation methods based on the plant parts used, the type of ailment being treated, the specific site of the ailment, and the intended form of application. The most common methods included crushing (49 instances or 29.87%), pounding (39 instances or 23.78%), chewing (16 instances or 9.75%), cooking (11 instances or 6.70%), smashing (8 instances or 4.87%), and boiling (7 instances or 4.26%). Other methods such as brushing, squeezing, smoking, and soaking were used less frequently. Leaves, roots, and barks were primarily prepared through crushing, pounding, and smashing, while harder parts like roots, barks, and stems were often cooked before further processing. Traditional practitioners also mix various additives—such as water, oil, sugar, salt, milk, honey, and coffee into their preparations to soften the medicine for patient consumption, enhance flavor, and mitigate adverse effects like vomiting and diarrhea. This aligns with [30], which states that many traditional remedies are prepared by combining multiple components to enhance their healing effectiveness while minimizing side effects for patients. The results of this study echo findings reported by [24, 46, 76].

Condition of preparation and rout of administration of medicinal plants

Traditional practitioners prepared medicinal plants in fresh, dry, and a combination of both conditions. According to informants in the study area, the majority of medicinal plants were prepared fresh, with respective numbers of 118 (71.95%), followed by 25 (15.24%) for dry and 21 (12.80%) for both dry and fresh. The preference for using fresh plant parts is attributed to their higher nutritional content and greater healing efficacy compared to dried ones. Plant parts that cannot be preserved for long periods are typically prepared fresh. In contrast, harder plant parts and some leaves are dried, crushed, and stored for extended use. The collection and storage of medicinal plants for long durations are crucial, especially when climatic conditions change and limit access to these resources in the field. In the study area, the practice of storing medicinal plants for extended periods is a unique cultural tradition known as Samo Eta. On October 17th each year, community members aged 10 and above participate in collecting medicinal plants, primarily from the mountainous regions, particularly Bori Mountain. This date is considered sacred by the Yem people, as it is associated with Orthodox Christianity and commemorates "Martyr St. Stephen." Stored medicines must be prepared carefully, covered with dry materials, and kept in a dry place. Traditional practitioners in the study area employ various routes of administration to treat patients, depending on the type of medicine used, the nature of the disease, and the patient's condition. The most common routes of administration identified were oral (65.8%), dermal (27.4%), nasal (4.8%), and auditory (1.8%). Respondents indicated that patients typically take traditional medicines orally for internal ailments and parasitic infections. Most oral medications are prepared in liquid form for easy consumption and distribution throughout the body. Other routes of administration are selected based on the specific conditions affecting the patient. These findings are consistent with similar research conducted by various scholars [76–77].

Dosage of administration and diagnostics features

In the study area, herbalists did not provide consistent or precise dosage prescriptions. Dosage varied based on the type of disease, the patient's condition, and their age. Informants indicated that doses were often estimated using various measuring tools such as liters, spoons, tea cups, coffee cups, water glasses, and even the palm of a hand. These estimations were tailored to the patient's age, the nature of the disease, and their overall condition. For children and patients who are more sensitive to the effects of medicines, smaller doses were typically prescribed. However, this reliance on estimations can lead to overdosing, which may result in serious complications, including death, while underdosing can prevent effective treatment. Local people have gained experience in recognizing appropriate quantities based on the physical condition of patients. The lack of consistent precision and standardization is a significant challenge within traditional medicine. This aligns with findings from previous studies ([30]), which highlighted the absence of precision and standardization as obstacles to the recognition of traditional healthcare systems. Similarly, [41] noted that imprecision in dosage is a major limitation of traditional remedies, corroborating the results of this study. According to informants, medicinal practitioners employed specific diagnostic features to determine prescribed doses according to the type of ailment. Healers typically diagnosed patients through interviews and visual inspections. They would ask patients or their attendants about observed symptoms and the duration of the health issue. Practitioners visually examined various indicators such as changes in eye color, urine, skin color, tongue and throat appearance, body temperature, swelling, edema, coughing, bleeding, diarrhea, vomiting, discharge of parasites, and the condition of sores for both humans and livestock.

Comparative analysis of medicinal plant species in present study and other regions of Ethiopia

Ethiopia is well known for its diverse ecosystems and a rich heritage of herbal medicine. Numerous studies have highlighted the ethnobotanical knowledge held by local communities regarding the medicinal use of plants. For instance, research conducted in the Yeki district of southwestern Ethiopia identified 98 species of medicinal plants [23], while another study documented 266 species in the Sheka Zone of the same region [41]. In the Quarit and Yilmana Densa districts of the West Gojam zone in northwestern Ethiopia, locals were found to utilize 112 medicinal plant species to treat ailments such as malaria, intestinal parasites, rabies, snake bites, evil spirits, and wounds, underscoring the significance of traditional knowledge [48]. Comparative studies have also demonstrated how this local knowledge contributes to biodiversity conservation [30]. Moreover, advanced pharmacological investigations have explored the antibacterial properties, antioxidant potential, and phytochemical profiles of selected medicinal plants in the Dibatie district of the Metekel zone and in Habru District, North Wollo Zone, Amhara Region, Ethiopia [78]. Our research identified 164 medicinal plant species used by the community in Yem, aligning with previous studies that reported 244, 81, and 78 species, respectively [30, 32, 33]. The traditional uses of various medicinal plants in Yem reflect trends observed in other regions. For example, B. pilosa is utilized for treating wounds, consistent with findings from [30], while D. stramonium is employed for ringworm, similar to its application in the Sheka zone of southwestern Ethiopia as noted by [41]. A recent study in the Yeki district highlighted the unique use of P. abyssinica Fresen, locally known as Yearo, which is used for typhoid by applying the leaves on the body while also consuming them orally [23]. Another study in the Guraferda district documented the use of C. mucronata for stomachaches, where the root is chewed, the juice consumed, and the abdomen gently smeared [30]. This ethnobotanical research has revealed previously unreported phytomedicines used in Yem and surrounding areas. Additionally, a separate study conducted in the Sheka zone of southwestern Ethiopia identified more novel species utilized by local communities [41], contributing to the expanding literature on Ethiopian ethnomedicine. These studies not only catalog the plants used but also explore their preparation and administration methods, offering valuable insights into traditional healthcare practices. Research into the pharmacological properties of traditionally used plants is on the rise. For instance, a study examining the antibacterial activity, antioxidant potential, and phytochemical profiles of selected medicinal plants in the Dibatie district of the Metekel zone and the Habru District in the North Wollo Zone of the Amhara Region, Ethiopia, revealed that certain plants believed to treat human ailments contain bioactive compounds with confirmed efficacy [78, 79]. These findings not only validate traditional claims but also encourage further exploration of their therapeutic potential.

The highest Jaccard's similarity index (JSI) recorded was 12.3% from a study conducted in Ameya [32], followed by 11.3% in Gurage, central Ethiopia [33], 10.9% in the Gera district [34], and 10.8% in Dawuro [17]. The JSI results indicate a gradual decline from the south-central, southwestern, and southeastern regions to the western, northern, northwestern, and northeastern parts of the country [23]. This trend is consistent with findings from Quara district in northwestern Ethiopia [31]. The high JSI between the current study and the Ameya district [32] can be attributed to their geographical proximity. The similarities observed among various regions in southwestern, south-central, and southeastern Ethiopia can be explained by several factors, including geographical features, cultural traditions, and types of vegetation. The similarities in ethnobotanical practices between the study area and certain other regions can be attributed to a combination of factors, including shared plant ecology, common linguistic ties, and overlapping customs. Ecologically, specific plant species may thrive in similar environmental conditions, leading to comparable uses and cultural significance across different communities. For instance, regions with similar climates and soil types typically support a similar range of flora, influencing local dietary practices and medicinal applications. Additionally, language plays a crucial role in the transmission of ethnobotanical knowledge; communities that share linguistic backgrounds often inherit similar customs and practices regarding plant use. This linguistic connection can facilitate the exchange of ideas and practices, further reinforcing the similarities in how plants are perceived and utilized. Ultimately, it is the interplay of these ecological and cultural factors that shapes the ethnobotanical landscape, highlighting the importance of both environmental conditions and cultural heritage in understanding the observed similarities across various regions [30, 31, 61]. The gradual decrease in JSI from southern to northern regions likely reflects the impact of distance and geographical barriers that hinder the exchange of information regarding the use of ethnomedicinal plants [31]. These findings indicate that traditional medicinal plant practices tend to be more consistent in areas that are geographically close and culturally similar, while diversity increases with greater distances and obstacles. This underscores the importance of considering regional and cultural factors when examining traditional plant-based healthcare practices. The shared use of certain species points to a common cultural heritage associated with traditional medicine in Ethiopia, whereas the unique practices observed in Yem highlight localized knowledge that warrants further exploration. This chapter illustrates that, while there is a robust foundation of shared knowledge about medicinal plants throughout Ethiopia, regional variations reflect adaptations to local environmental conditions and cultural traditions. Despite the rich heritage of traditional medicine, various threats jeopardize the sustainability of medicinal plant resources in Ethiopia, including the study area. Deforestation, land degradation, and climate change present significant challenges to biodiversity and the availability of medicinal plants. Research has shown that habitat loss due to agricultural expansion and urbanization has led to the decline of many plant species traditionally used for medicinal purposes [4, 30, 43]. The insights gained from this comparative analysis suggest several potential avenues for future research, including biodiversity conservation, understanding how local practices contribute to the preservation of medicinal plant species, conducting phytochemical studies to explore the bioactive compounds in uniquely utilized species from Yem, and documenting cultural heritage to safeguard local knowledge systems related to ethnomedicine.

Implications of utilizing medicinal plants in the study area

The findings of this study on the traditionally used medicinal plants in the Yem district of Central Ethiopia have significant implications for environmental sustainability, food security, and public health. The region's rich biodiversity in medicinal plants highlights the importance of traditional knowledge systems in maintaining ecological balance and promoting sustainable practices. However, challenges such as habitat loss, overharvesting, and climate change pose serious threats to local flora and the livelihoods that depend on them. Regarding food security, the study emphasizes the vital role of traditional knowledge in utilizing plants for health and nutrition. A decline or loss of this knowledge could jeopardize food security, as many medicinal plants also serve as food supplements. Additionally, most of the medicinal plants used by the community are harvested or cultivated locally. A decrease in their availability could negatively impact local economies that rely on the harvesting and sale of these plants, exacerbating poverty and further threatening food security as households may struggle to afford adequate food and healthcare. Traditional knowledge surrounding the preparation and consumption of these plants can play a crucial role in addressing malnutrition and promoting dietary diversity. Examples of medicinal plants that also serve as food include M. esculenta, S. americanum, and C. abyssinica. Economically, the sale of medicinal plants such as C. arabica, H. rueppelli, R. chalepensis, C. edulis, A. abyssinica, and E. kebericho provides income opportunities for local communities, helping families facing food insecurity access essential goods. Promoting sustainable harvesting and cultivation of these plants can enhance resilient livelihoods and reduce dependence on external food sources [23].

The decline of these medicinal plants could lead to reduced dietary diversity and exacerbate malnutrition, particularly among vulnerable populations. The variety of medicinal plants present in the Yem district underscores the region's ecological richness. The local community's reliance on these native species is crucial for biodiversity conservation. Traditional knowledge promotes sustainable harvesting practices, which help prevent overexploitation. Furthermore, many medicinal plants play a significant role in habitat restoration, aiding in soil stabilization and providing shelter for various wildlifes, thereby enhancing overall ecosystem health. Medicinal plants also offer essential ecosystem services to the community, such as attracting pollinators that are vital for the productivity of both wild and cultivated crops and improving soil health through processes like nitrogen fixation and the enhancement of organic matter. From a public health perspective, this study emphasizes the importance of integrating traditional medicine into formal healthcare systems. Many communities rely on these phytomedicines to address various health issues, with their effectiveness often rooted in centuries of empirical knowledge. However, threats to these resources could increase dependence on synthetic pharmaceuticals, which may be less accessible or culturally accepted in these communities. Protecting and promoting the sustainable use of traditional medicines can enhance public health outcomes by providing affordable and culturally appropriate healthcare options. This study thus highlights the interconnectedness of environmental integrity, food security, and public health in the Yem district. Addressing the threats to traditionally used medicinal plants is vital for fostering a sustainable future that honors local traditions while safeguarding both ecological and human health. These findings align with reports by [31, 41, 43].

Quantitative analysis of ethnobotanical data (ICF, FL, DMR, and PR)

Various quantitative tools were utilized to assess the biodiversity of medicinal plant species in the study area and the high level of community acceptance regarding their medicinal value. Informant consensus factors, fidelity levels, direct matrix ranking, and preference ranking were employed to illustrate the agreement among community members on the presence of diverse medicinal plants used for treating different ailments. The informant consensus factor (ICF) highlighted the most prevalent diseases in the area and the community's shared understanding of remedies used for these ailments. The results indicated that medicinal plants recognized by community members as effective for specific diseases tend to have higher ICF values. This finding aligns with previous reports by [41, 75], which noted that plants believed to be effective for certain diseases also exhibit elevated ICF values. In this study, respiratory system-related diseases had the highest ICF value at 0.91, followed closely by conditions associated with the evil eye and evil spir