The present invention includes methods and compositions for the treatment and prevention of protozoal parasitic infections utilizing Diindolylmethane-related indoles. Additive and synergistic interaction of Diindolylmethane-related indoles with other known anti-parasitic and pro-apoptotic agents is believed to permit more effective therapy and prevention of protozoal parasitic infections. The methods and compositions described provide new treatment of protozoal parasitic diseases of mammals and birds including malaria, leishmaniasis, trypanosomiasis, trichomoniasis, neosporosis and coccidiosis.