Feverfew is an herbal supplement used primarily to prevent migraines. It belongs to the daisy family and has been used for centuries to treat headaches, fever, and inflammatory conditions like arthritis. Today, its main evidence-backed use is reducing the frequency of migraine attacks, though it also has documented anti-inflammatory and blood-thinning properties.
Migraine Prevention
The strongest case for feverfew is in preventing migraines, not treating them once they start. The herb works by blocking inflammatory pathways and reducing the release of chemical signals involved in blood vessel constriction and pain. Its key active compound inhibits a protein called NF-κB, which acts as a master switch for inflammation throughout the body.
Clinical trials back this up with real numbers. The largest rigorous trial, involving 218 participants, found that feverfew reduced migraine frequency from 4.8 attacks per month to 2.9, compared to a drop from 4.8 to 3.5 in the placebo group. That’s roughly one fewer migraine per month than placebo. About 30% of people taking feverfew were classified as responders, compared to 17% on placebo. The total number of migraine days per month also dropped significantly.
Earlier crossover trials, where participants switched between feverfew and placebo, revealed something telling: people who stopped taking feverfew and switched to placebo saw their migraine frequency jump back up (averaging 3.1 attacks per month), while those who continued on feverfew held steady at 1.7. Nausea and vomiting during attacks also dropped sharply. In one trial, 42% of attacks involved nausea in the feverfew group versus 79% on placebo. For people with migraine with aura specifically, the benefit was more pronounced, with attack frequency dropping from 4.3 to 2.9 per two-month period.
Anti-Inflammatory and Anti-Clotting Effects
Beyond migraines, feverfew has been used as a traditional remedy for arthritis and other inflammatory conditions. The biological basis for this is the same NF-κB inhibition that makes it useful for migraines. By dialing down this inflammatory signaling pathway, the herb can reduce the cascade of swelling and pain that characterizes conditions like rheumatoid arthritis. However, the clinical evidence for arthritis is much thinner than for migraines.
Feverfew also has measurable effects on blood clotting. Lab studies show it inhibits platelet clumping in a dose-dependent way, meaning higher concentrations produce a stronger anti-clotting effect. This happens through multiple mechanisms, including changes in how the body processes arachidonic acid, a fatty acid central to both inflammation and clot formation. This anti-clotting potential is important to keep in mind if you take blood-thinning medications or antiplatelet drugs, since feverfew could amplify their effects.
How to Take Feverfew
Feverfew supplements come in several forms: fresh leaves, freeze-dried capsules, dried leaf tablets, and liquid extracts. For migraine prevention, the standard recommendation is 125 mg daily of a dried leaf preparation standardized to contain at least 0.2% parthenolide, which is the herb’s primary active compound. Some products use higher doses of 100 to 300 mg up to four times daily, standardized to 0.2 to 0.4% parthenolide. CO2-extracted versions are more concentrated, with a typical dose of 6.25 mg taken three times daily.
Standardization matters here. Feverfew products vary widely in their parthenolide content, and supplements that don’t guarantee at least 0.2% parthenolide may not deliver a meaningful dose. Look for this specification on the label. Most clinical trials ran for 12 to 16 weeks before measuring results, so it’s not a quick fix. You need consistent daily use over several months to see whether it works for you.
Side Effects and Withdrawal
Feverfew is generally well tolerated, but it does have some notable side effects. Chewing fresh leaves can cause mouth ulcers, which is why capsules or tablets are the preferred form. Digestive discomfort is the most common complaint.
One unusual risk is post-feverfew syndrome, a withdrawal reaction that can happen after stopping the herb following long-term use. Symptoms include muscle stiffness, anxiety, moderate pain, headaches, nausea, and vomiting. The headaches during withdrawal are particularly ironic given the herb’s purpose. If you’ve been taking feverfew regularly, tapering off gradually rather than stopping abruptly is a reasonable approach.
Who Should Avoid Feverfew
Pregnant women should not take feverfew because it may stimulate uterine contractions. Anyone with an allergy to plants in the Asteraceae (daisy) family should also avoid it. This family includes ragweed, chamomile, echinacea, and milk thistle, and cross-reactivity between these plants is well documented. If you react to any of those, feverfew could trigger a similar allergic response.
Because of its anti-clotting properties, feverfew is a concern for people taking anticoagulant or antiplatelet medications. The combination could increase bleeding risk. The same caution applies before surgery, since reduced clotting ability could complicate the procedure.