A survey was conducted of medicinal plants for gastrointestinal disorders used by inhabitants of the Central Valley in Costa Rica by menas of interviews with medicinal plant vendors of the central markets of the cities of Alajuela, Cartago, Heredia and San José. Fifteen medicinal plants and one plant mixture were recorded; the last one was prepared in situ by the vendor upon request and its component varied according to the availability of plants. A qualitative chromatographic comparison was made on the patterns of plants from different origin and different times of the year. A quantitative method using HPLC was used to examine Quassia amara and Plantago major.
