G. Schmeda-Hirschmann, J. I. Loyola, J. Sierra, R. Retamal, J. Rodriguez. Departamento de Biologia, Universidad de Talca, Casilla 747, Talca, Chile.Thirty-five plant samples belonging to 30 Mapuche medicinal plants were assayed for xanthine oxidase and -glucuronidase inhibitory activity as well as for brine shrimp toxicity and hypotensive effect in normotensive rats. A high number of extracts displayed significant inhibition towards the enzyme -glucuronidase or elicited a hypotensive response. The biological activity of the assayed extracts shows some correlation with their use as digestives for treating hepatic troubles by the Mapuche Amerindians. From the ten plants displaying a hypotensive effect 20%, eight have some ethnobotanical indication suggesting that activity.