Background and purpose: Saponaria officinalis is a plant from the caryophyllaceae family and there are some contradictory reports about its antimicrobial effects. Metronidazole is commonly used in treatment of trichomoniasis but it has several side effects. On the other hand, finding an alternative drug from natural sources is very important. This study aimed at evaluating the hydroalcoholic extract of Saponaria officinalis leaf plant on the growth of Trichomonas vaginalis in vitro.

Materials and methods: The plant was approved in herbarium and hydro-alcoholic extracts were prepared. The experiment was done using 24 wells cell culture plate. In each well,  200 microliter of  TYM culture medium and 200 microliter of different concentrations of plant extract was added. Also metronidazole was added to positive control well. Then 100 µl TYM were added to all wells containing 500,000 parasites and the plates were incubated at 37 ° C. The experiment was performed as double blind and triplicate. The mean number of the parasites in different concentrations and times and effect of the extract were recorded.

Results: The number of parasites in 50, 100, 200, 400, 800 and 1600 micrograms per ml of the extract, during 24, 48, and 72 hr increased compared to the negative controls, while no growth of parasite was observed in positive controls (containing Metronidazole).

Conclusion: Saponaria officinalis leaf extract caused growth stimulation and increased the number of Trichomonas vaginalis, therefore, it could be used for mass cultivation of the parasite in vitro. However, further investigations are needed in future.