Abstract In the high Amazonian basin a plant named chuchuasha, (or chuchuaso) is used in traditional medicine for several purposes in the form of an alcoholic extract. This plant, a Maytenus species, most probably Maytenus laevis, grows in the subandean region of the Amazonian basin (Peru, Ecuador, Colombia). Antitumor and anti-inflammatory properties were recently attributed to the extracts of the root bark of the plant. The composition of the extract of M. laevis from the Putumayo area of Colombia was studied in order to establish the active principle responsible for these activities. The presence of phenoldienones (tingenone, 22-hydroxytingenone), a catechin (4'-methyl-(—)-epigallocatechin) and proanthocyanidins (Ouratea-proanthocyanidins A and B) was established. The biological activities of these compounds confirm the properties of the extracts of the plant claimed by traditional medicine.