Background: Heavy menstrual bleeding is one of the leading causes of low quality of life and iron deficiency anemia in women of reproductive age. This study was conducted to compare the therapeutic effects of mefenamic acid and the hydroalcoholic extract of Urtica dioica on the volume of bleeding in heavy menstrual bleeding.

Materials and Methods: In this clinical trial, 90 women with heavy menstrual bleeding were selected and after a control cycle for evaluating the primary bleeding volume, using Excel software, were randomly allocated to Urtica dioica or control groups. Both groups were subjected to mefenamic acid treatment with 500 mg every 8 hours, from the first day to the end of bleeding, up to seven days, for two consecutive cycles. In Urtica dioica group, in addition to mefenamic acid, Urtica dioica capsules, five per day, two in the morning, two at noon, and one at night (every eight hours), from the first day to the end of bleeding, up to seven days, were prescribed. In the control group, instead of Urtica dioica capsules, placebo of Urtica dioica was prescribed with the same order. Data on the amount of bleeding (using PLBAC chart) was checked and compared by SPSS software.

Results: The amount of bleeding before and after treatment, between and within groups, was compared. The obtained results showed that the amount of bleeding reduced significantly in both groups after treatment (p=0.001). The reduction of bleeding amount in the Urtica dioica group was significantly higher than that in the control group (p=0.010).

Conclusion: It seems the extract of Urtica dioica can be effective in reducing the amount of bleeding in women of reproductive age with heavy menstrual bleeding. This drug, due to its short course of prescription, fewer side effects, and not having hormonal effects, seems to be an effective drug for treating heavy menstrual bleeding.