Medicinal plants in homegardens of four ethnic groups in Thailand.
Ethnopharmacological relevance: Homegardens are important habitats for medicinal plants and traditional knowledge, especially among indigenous groups in remote areas. In homegardens, medicinal plants and traditional knowledge are well conserved through human management and ease of access. Aim of the study: To understand the drivers of diversity and the composition of homegardens with focus on medicinal plants, including exotic species, and their uses. We compare the homegardens of four ethnic groups in northern Thailand (Thai Yuan, Lahu, Karen, and Lisu). Methods: We inventoried all medicinal species in 195 homegardens from four villages belonging to the four ethnic groups. The owners were asked to point out all useful species in their homegardens. For any medicinal species, they were then interviewed about their main and secondary uses, medicinal properties, plant part used, preparation methods, and route of administrations. Results: We recorded 95 medicinal homegarden plant species ranging from 20-59 species per village and ethnic group. Most of the medicinal plants had a primary use as food plants, which demonstrated the close relationship between local food and medicine in the lives of these ethnic groups. Many of the medicinal plants were also used as food additives, ornamentals, or materials, showing that medicinal plants are not an exclusive category in the homegardens. The number of homegarden plants varied almost four-fold from 58 species in one village to 211 in the most species rich village. The number of medicinal homegarden plants varied accordingly from 20 to 59 in the poorest and the richest villages. Five medicinal species were found in all villages, but 70% of the medicinal plants were found in only one village. Infection & infestation, Nutritional disorders, and Digestive system disorders were the three most important medicinal use categories for plants in the homegardens, and all three categories were found in most of the studied homegardens. Of the 95 species with medicinal uses, 26 (27%) were exotic, which shows that local people amplify the spectrum of alternative ways to treat their illnesses. Conclusion: Homegardens are an important source of ethnomedicinal species and knowledge. These species are beneficial for treating acute and common ailments; they are easy to access and can be prepared by simple methods, which are suitable for treating disorders, such as infections or any digestive system ailments. Medicinal plants in homegardens have been important in improving health, at least, at the family level.