BackgroundThe Shui are a small Chinese sociolinguistic group living in Sandu Shui Autonomous County, south of Guizhou Province. The Shui people have accumulated and developed rich traditional medicinal knowledge, which has played a significant role in their healthcare. Traditional ethnic herbal medicines, like Shui ethnomedicine, have become an important resource of rural development in Guizhou Province. However, not much research has been conducted to document the medicinal plants traditionally used by the Shui people. This study’s aims are (1) to record the current use of medicinal plants in Sandu County and associated traditional knowledge, including the medicinal plant species used and the types of diseases treated by local healers and any unique aspects of their preparations; (2) to analyze the most important medicinal plant species using relative frequency of citation (RFC); and (3) to provide useful information and data for possible future development and application of ethnomedicine and promote the conservation and preservation of Shui traditional medicinal knowledge.MethodsField surveys were conducted between July 2015 and August 2022 in Sandu County. A total of 15 local healers as key informants were interviewed. An additional 132 informants from villages and local markets were also interviewed through semistructured interviews and focal group discussions. Local Shui healers were followed during their collection of medicinal plants in the fields and recorded the medicinal plants’ names, uses, and parts used. An ANOVA was used to evaluate the number of medicinal plants recognized by local healers across age-groups and townships, and relative frequencies of citation values were determined for the recorded medicinal plants.ResultsIn this study, data collected from 15 Shui healers and 132 other informants were analyzed. The healers used fresh or dried parts of 505 plant species as medicine to treat a wide range of conditions and diseases. These plants belong to 405 genera from 156 families, with Fabaceae being the highest represented plant family. The Jiuqian township had the highest distribution of per capita healers (pch); only one local healer was in Zhonghe. Of the 15 local healers, only two were younger than 40 years of age. There is a major concern that traditional medicinal knowledge may be lost if there are not sufficient trainees or suitable successors. Among the common medicinal plants, most are herbaceous and the Shui typically use the whole plant in their medicines. There are 85 different recorded diseases treated by Shui medicinal plants, and among them, rheumatism and bone fractures have the largest number of species used. Three medicinal plant species,Isodon amethystoides,Asarum insigne, andAcorus tatarinowii, are the most commonly used ethnomedicines by the Shui people.ConclusionThis study demonstrated that Shui people have extensive knowledge of a diverse range of medicinal plants, many of which had not been systematically recorded before the current study. Further research on the chemistry, pharmacology, and toxicity of Shui medicinal plants will be useful for developing functional foods or pharmaceutical products, particularly those ofIsodon amethystoides,Asarum insigne, andAcorus tatarinowii. Additionally, as a result of rapid economic growth, fewer young people in Shui communities pursue traditional medicinal studies. Only 15 traditional Shui healers remain in the county, and only two of them are below the age of 40 years. Therefore, to conserve Shui’s traditional medicinal knowledge, initiatives and policies are required to regenerate, strengthen, and promote Shui medicinal knowledge.