Chagas' disease, a vector-transmitted infectious disease, is caused by the protozoa parasite Trypanosoma cruzi. Drugs that are currently available for the treatment of this disease are unsatisfactory, making the search for new chemotherapeutic agents a priority. We recently described the trypanocidal action of (-)-elatol, extracted from the macroalga Laurencia dendroidea. However, nothing has been described about the mechanism of action of this compound on amastigotes that are involved in the chronic phase of Chagas' disease. The goal of the present study was to evaluate the effect of (-)-elatol on the formation of superoxide anions (O2•-), DNA fragmentation, and autophagy in amastigotes of T. cruzi to elucidate the possible mechanism of the trypanocidal action of (-)-elatol. Treatment of the amastigotes with (-)-elatol increased the formation of O2•- at all concentrations of (-)-elatol assayed compared with untreated parasites. Increased fluorescence was observed in parasites treated with (-)-elatol, indicating DNA fragmentation and the formation of autophagic compartments. The results suggest that the trypanocidal action of (-)-elatol might involve the induction of the autophagic and apoptotic death pathways triggered by an imbalance of the parasite's redox metabolism.