Euphol is a tetracyclic triterpene found in species of Euphorbiacea family. It has shown cytotoxic, anti-inflamatory and antinoception activity. The cytotoxic effect was demonstrated against Jukat (acute leukemia), T47D (breast cancer) and CS12 (gastric carcinoma) cells lines. The aim of this study was evaluated the cytotoxic activity of euphol (using MTT reduction assay) on K-562 (chronic leukemia) cell line and study its selectivity (were used lymphocytes and monocytes from human blood, obtained from healthy volunteers (COEP 1.026.524)). The euphol was obtained from Euphorbia umbellata (Pax) Bruyns latex by acid precipitation and chromatography column procedure, so the precipitated obtained was conditioned in a column and eluted with hexane, ethyl acetate and mixture of these two solvents in different concentrations. It was obtained 666 fractions (25 mL) that were polled according their retention time (observed in a CCD analysis). The polled fraction 244-255 was analyzed using NMR and GC-MS techniques and the identification was determined by 1D and 2Dexperiments and NIST library. The cytotoxicity was evaluated after 24, 48 and 72 hours of treatment. The selectivity was calculated as the ratio of IC50 of lymphocytes or monocytes and K-562 cells after 48 hours of treatment. Euphol was able to reduce de viability of K-562 cells with IC50 of 40.6±3.9µM, 34.4±2.1µM and 34.6±2.1µM, for 24, 48 and 72 hours, respectively. For the selective assay, the index obtained was 2.08 for the lymphocytes and 2.36 for the monocytes. Data shows that euphol can reduce cell viability and was selective when compared with lymphocytes and monocytes.