oral fennel (foeniculum vulgare) drop effect on primary dysmenorrhea: effectiveness of herbal drug

background: primary dysmenorrhea refers to the occurrence of painful menstrual cramps of uterus and is considered as a gynecological complaint. the common treatment for this problem is medical therapy such as mefenamic acid [non‑steroidal anti‑inflammatory drugs (nsaids)] and oral contraceptive pills, both of which work by reducing myometrial activity. fennel contains an antispasmodic and anethol agents and may be helpful for management of primary dysmenorrhea. material and methods: the aim of this study was to evaluate the effects of oral fennel drop for treating primary dysmenorrhea. in this randomized clinical trial study, fennel drop 2% was compared with mefenamic acid for reducing pain of primary dysmenorrhea. sixty college students suffering from primary dysmenorrhea were randomly assigned to two groups and followed up for two cycles. statistical analysis was performed using spss version 16. p < 0.05 was considered to be statistically significant. parametric and non‑parametric tests were adopted. results: comparison of pain intensity in the two groups showed that there was no significant difference in pain relief between the two groups. comparison of bleeding severity in the study group before and after intervention was demonstrated from the first day to the fifth day (pv on first day, second day, third day, fourth day, and fifth day 0.948, 0.330, 0.508, 0.583, 0.890, respectively). conclusion: it seems that fennel can be effective in reducing the severity of dysmenorrhea, but it has an unpleasant taste in view of most of the volunteers.