Jasmonates are a group of small lipids produced in plants, which function as plant stress hormones. We have previously shown that jasmonates can exert significant cytotoxic effects upon human cancer cells. The purpose of the present study was to determine the effects of jasmonates on parasites. To that end, we chose 2 major human blood parasites, Plasmodium falciparum, a unicellular parasite, and Schistosoma mansoni, a multicellular helminth parasite, and studied the effects of jasmonates on these parasites in vitro. We found that jasmonates are cytotoxic toward both parasites, with P. falciparum being the more susceptible. Jasmonates did not cause any damage to control human erythrocytes at the maximum concentration used in the experiments. This is the first study demonstrating the antiparasitic potential of plant-derived jasmonates.