Background: Trichomonas vaginalis is the most common curable sexually transmitted disease world wide. In view of increased resistance of the parasite to classical drugs of the metronidazole family, the need for new unrelated agents is increasing. In Charmahal va bakhtiare province Stachys lavandulifolia traditionally used for vaginal infection.

Objective: The study evaluates anti trichmonas activity of of ethanolic and watery extract of aerial parts Stachys lavandulifolia.

Methods: This study has been carried out as double blind in test and control groups. Etanolic and watery were extracted by hydro distillations. The parasite was isolated from vagina. Sample were collected from vaginal discharges of six patients and cultured in laboratory. Identification were done through direct smear preparation, parasite was added to the 9 test tubes containing metronidazole, etanolic and watery extraction of Stachys lavandulifolia with concentration of (10, 50, 100, 200, 500 and 1000μL/ml) order to determine the effect of these concentration within 72 hours.

Results: finding suggested that the Trichomonas vaginalis could be alive in TYIS-33, watery and ethanolic extraction within 72 hours. In presence of metronidazole for no alive parasite was detected after 72 hours. Number of parasite in TYIS-33, watery (10, 50, 100, 200, 500 and 1000μg/ml) and ethanolic extraction (10, 50, 100, 200, 500 and 1000μg/ml) and ethanol was 1504, 1504, 100, 1304, <100, 577 respectively.