This study evaluates the in vitro anti-trichomonads activity of a saponin enriched fraction
(MSF) obtained from the fruits of Ilex paraguariensis A. St. Hil. (Aquifoliaceae). The MSF showed better
anti-trichomonads activity than polysorbate and tyloxapol. A similar activity was obtained for quillaja
saponins, but this fraction presented the highest cytotoxicity to mammalian cells as follows: quillaja > tyloxapol
> polysorbate 80 > MSF. Neither the co-addition of MSF and metronidazole (MTZ) nor the pretreatment
of the trophozoites with MSF prior to the addition of MTZ elicited a significant effect on MTZ
activity.