this work describes an ethnobotanical survey of medicinal plants in santo antonio do leverger municipality, mato grosso state, brazil and estimates the diversity of species with therapeutic use. adult dwellers, male and female, were interviewed and plant gathering undertaken with their assistance. voucher specimens were deposited at the herbarium rioclarense (hrcb). 228 species were identified, belonging to 73 families; 56% of the species grow spontaneously in natural and anthropically modified habitats, 41% are cultivated and 3% are purchased. diversity indexes are among the highest ones reported in literature for medicinal plants in other tropical areas. richness and diversity of spontaneous species may mirror to certain extent environmental richness and diversity, whereas for cultivated species, these measures could be linked to socio-cultural factors enhancing introduction of new plants and use information from outside the area. it is suggested that when traditional communities become more exposed to society at large, species number and knowledge about their use may at first increase, by foreign input; but, with the socio-economic changes that come about over time, plants used for therapeutic aims will be limited to the cultivated species and cosmopolite weeds.