The drugs presently in use against Chagas disease are very toxic, inducing a great number of side effects. Alternative treatments are necessary, not only for Chagas disease but also for other diseases caused by protozoan parasites where current drugs pose toxicity problems. The plant microtubule inhibitor trifluralin has previously been tested with success against Leishmania, Trypanosoma brucei and several other protozoan parasites. Trypanosoma cruzi, the causative agent of Chagas disease, is also sensitive to the drug. This sensitivity has been correlated with the deduced amino acid sequences of alpha- and beta-tubulin of T. cruzi as compared with plant, mammal and other parasite sequences.