Cnidoscolus quercifolius is an Euphorbiaceae endemic to the northeast region of Brazil, which is used in folk medicine as anti-inflammatory, analgesic and antibiotic. An ethanolic extract was prepared with the leaves from C. quercifolius, and also partitioned and chromatographed leading to the isolation of cyanoglucoside linamarin (1), cinnamic acid (2), as well as a mixture of steroids and terpenoids (3 -6). Structural elucidation of the compounds was done by IR, MS and NMR analysis. For the cyanoglucoside (1) were also evaluated its antimicrobial and antileishmanial viabilities by plaque microdilution and MTT test, respectively. Both tests showed from moderate to zero activity against the organisms evaluated. In addition, the antiproliferative activity of compounds 1 and 5-6 were tested against tumor cells, which did not show statistically significant growth inhibition 50% (GI 50 ). The obtained results suggested that further pharmacological studies should prove the folk medicinal uses.