Blood trnasfusion is the second most importnatmechanism of transmission of Chagas'disease in both endemic and non-endemic areas. In Latin America, more than 20,000 cases of transmission of the disease, trough blood transfusion, may be occurring. Gentian Violet is currently the only available trypanicidal agent used for treating blood before transfusion. The main disadvantages of this treatment are the time required to allow drug action before transfusion and the coloring of the blood. In vitro trypanocidal effect of plant extracts and that of pure compounds are assessed against trypomastigote blood forms of T. cruzi. The induction of sister chromatid exchange (SCE) in human lypocytes was performed to evaluate mutagenic effects of these compounds. Eight compounds had a high activity against blood forms of T. cruzi at a concentration of 250 mg/ml; namely, daphnandrine, limacine, pheantine, daphnoline and cocsuline. Plumbagin (a naphthoquinone) also showed high trypanicidal activity and has previously been recognized as a leismaniacidal, bactericidal and fungicidal, compound. Daphnoline showed low values for both LC50 (8mg/ml) and LC90 (50mg/ml) and was the only tested compound which did not induce sister chromatid exchange below 10 mg/ml. Therefore, deeper evaluations of these compounds should be considered