The aqueous and ethanol extracts of the root bark of Hippocratea excelsa HBK. Locally known as 'Cancerina', showed an important gastroprotective effect in several experimental ulcer models in rats. Fractionation of the methanol extract led to four pools of active fractions (F1-F4). Sitosterol-3-O-beta-glucoside, beta-sitosterol and (-) epicatechin were isolated from the active fractions and showed an important gastroprotective activity (93.4,85.7 and 72.1% of gastroprotection, respectively), whereas bismuth subsalicylate, used as positive control, showed 46.2% of gastroprotection. A mixture of alpha-amyrin and beta-amyrin showed 50% of gastroprotection. Friedelin, canophyllal and canophyllol were isolated from the active fractions, but they were inactive as gastroprotective compounds. These results provide additional support for the popular use of this plant as an antiulcer remedy in the Mexican traditional medicine.