Introduction & Objective: Most women in the course of their lives will experience menstrual bleeding. Some have bleeding almost all the time. Different approaches have been proposed and drugs with fewer side effects are preferred. The aim of this study was to compare the ef-fects of herbal medicines (fennelin & vitagnus) and mefenamic acid in the treatment of severity of menstrual bleeding.

 Materials & Methods: This double blind clinical trial was carried out in one hundred and five students with severe menstrual bleeding at Hamadan University of medical sciences in 2010. The students were randomly grouped in four groups and herbal medicines of fennelin & vitagnus, mefenamic acid and placebo. The severity of menstrual bleeding was detected by the Higham table during one cycle before and two cycles after the intervention. The data analyzed by SPSS/16 and P<0.05 was considered significant.

Results: Demographic characteristics of the students were similar in the four groups. There was not a significant difference in the mean of severity of menstrual bleeding during the one cycle before intervention between the four groups, but the difference was significant dur-ing the two cycles after the intervention. Mefenamic acid reduces menstrual bleeding com-pared with vitagnus & fennelin and showed no statistically significant difference.

 Conclusion: All three drugs mefenamic acid, fennelin and vitagnus have been effective in reducing menstrual bleeding. The two herbal medicines (vitagnus and fennelin) can be used as effective and safe drugs to reduce menstrual bleeding.