Gastrointestinal disorders are one of the major health problems in developing countries. Sixty-five plants used popularly in the treatment of such disorders in a Mixe Indian community in Oaxaca (Mexico) and collected during a fieldstudy of 15 months are described. According to indigenous criteria a plant is used in the treatment of a certain illness because of the plant's characteristic smell and taste. Plants with astringent properties are particularly valued to treat diarrhoea and dysentery. Bitter, aromatic and bitter-aromatic plants are especially employed to treat gastrointestinal cramps and pain. Additionally, the efficacy of these plants was evaluated using ethnobotanical, phytochemical and pharmacologic information on the plants. The majority of the plants contain chemicals that may produce the effects desired by the Mixe. Frequently tannin-containing drugs are used to treat diarrhoea and dysentery. A large number of the plants used by the Mixe in the treatment of gastrointestinal pain contain essential oil or bitter principles. As a result of this evaluation, plants were selected which should be studied phytochemically and pharmacologically with priority, to evaluate further their potential in the treatment of gastrointestinal disorders.