Tanacetum parthenium (feverfew) is a member of the daisy family; it is used to prevent and treat migraine and rheumatoid arthritis. It has a long history of use as a traditional and folk medicine in Chinese, Greek, Indian and Arabic medicine, having been used for hundreds of years. The term feverfew comes from the Latin word febrifugia and means fever reducer. However, Short term use of feverfew (up to 4 months) is considered safe in adults. According to a few clinical trials, Tanacetum parthenium was not associated with serious adverse events but rather with mild and reversible events. Adverse events leading to withdrawals were mainly of a gastrointestinal nature. There is no major safety issue. Nevertheless, we report one case of a 36-year-old woman with known migraine who visited the obstetrics and gynecology clinic upon developing vaginal bleeding, prolonged duration of the menstrual cycle, and reddish skin without bruising. The patient suffered from these symptoms over a period of 3 months prior to the clinic visit. Based on history, the patient began taking 800 mg capsules of feverfew three times per day 9 months ago. We applied the Naranjo scale in our case, and it indicated that a probable relationship exists between feverfew and vaginal bleeding. Feverfew should be used cautiously by patients planning elective surgery, having coagulant disorders or taking antithrombotic drugs.