**1. Introduction**

Indonesia has around 25,000-30,000 species of plants and is inhabited by around 300- 700 ethnicities. These ethnic groups use it for various purposes, one of which is for medicinal purposes. The use of plants as medicinal substances is mostly passed down orally, so they are prone to degradation. Ethnomedicine study is a method that can be used to document the use of plants by ethnic groups with scientifically acceptable research methods. This paper aims to explain the study of ethnomedicine especially in West Sumatra and its research methods.

One of the local wisdoms possessed by Indonesians is to utilize the natural biological resources in the vicinity. Every local community uses their vegetable resources to fulfill their daily needs, one of which is to maintain their health which is known as medicinal plants. Knowledge on the use of medicinal plants is generally passed down orally, so that knowledge is limited to certain groups of people and is susceptible to degradation due to cultural acculturation and modernization.

#### *Natural Medicinal Plants*

The use of plants to maintain health has long been carried out in Indonesia in line with the development of civilization. Indonesia has been formulating and using medicinal plants (traditional medicine) since the era of Hindu-Javanese kingdom. In West Sumatra itself, medicinal plants have been an alternative treatment since the time of our ancestors. One of the plants that is widely used in the experiment is the soursop plant (Latin name), betel plant (Latin name) and castor plant (Latin name). The part of the plant that is used as medicine is the leaves.
