Feverfew is a bushy perennial herb. The dried leaves are used in capsules, tablets, and liquid extracts. Parthenolide and glycosides are thought to be its active components.
People take feverfew mostly to prevent migraine headaches. Evidence from three of four relatively small but well-designed studies supports these claims, but the largest and best designed of these studies did not. Differences in study findings may reflect the different formulations of feverfew used. In studies of people with arthritis, feverfew did not relieve symptoms. It has also been used to treat fevers, toothaches, insect bites, infertility, psoriasis, allergies, ringing in the ears (tinnitus), dizziness, nausea, vomiting, and problems during childbirth.
Mouth ulcers and skin inflammation (dermatitis) may occur. Taste may be altered, and heart rate may be increased. Feverfew may interact with drugs that prevent blood clots (anticoagulants), drugs used to manage migraine headaches, and nonsteroidal anti-inflammatory drugs (NSAIDs). It may reduce the normal clotting tendency of particles in the blood that help stop bleeding (platelets) and may reduce the absorption of iron. Feverfew is not recommended for children or for women who are pregnant or breastfeeding. In addition, feverfew may cause allergic rashes.