Feverfew, Tanacetum parthenium, is mainly used in the prevention of migraine headaches. It belongs to the sunflower family, and its flowers are small and daisy-like with yellow disks and 10 to 20 white, toothed rays. It is also known as Chrysanthemum Parthenium, Featherfew or Midsummer Daisy.

Feverfew has been used for centuries as a febrifuge (fever reducer) and for the treatment of migraines and arthritis. Other historical uses include the treatment of anemia, earache, dysmenorrhea, dyspepsia, trauma and intestinal parasites. It has also been used in gardens to control noxious pests (its pyrethrin component is an effective insecticide and herbicide).

Preventive Treatment for Migraine

Feverfew has been shown to decrease the frequency and/or intensity of migraine attacks. Although the exact mechanism is still unknown, the efficacy of feverfew in the prevention of migraine headaches is probably due to its ability to:

1. Inhibit the secretion of serotonin (a vasoconstrictor) from platelets.
2. Decrease blood vessel response to vasoconstrictors (e.g., adrenaline, acetyl choline, prostaglandins and serotonin).
3. Inhibit the production of inflammatory agents such as prostaglandins.

Migraine headaches appear to have an initial ischemic (deficiency of blood) area in the brain. Cerebral vasodilation and inflammation usually follow any ischemic event, resulting in a pounding headache. The physiological mechanism of migraine involves platelet function, vasospasm due to vasoactive amines, and inflammation.

Feverfew seems to reverse or reduce the sensitivity of the mechanisms that leads to a migraine attack. Unfortunately, it does not work right away, and takes some time to exert its action on platelet aggregation (resulting in a decrease in secretion of serotonin), and on inhibiting the production of inflammatory substances. Therefore, feverfew is only effective in the prevention of migraines by taking it regularly, and is not effective in treating acute migraine attacks.

The historical use of feverfew in the treatment of inflammatory conditions such as rheumatoid arthritis is probably due to the actions mentioned above. In experimental studies, researchers have actually shown extracts of feverfew to have greater activity in inhibiting inflammation and fever than aspirin. They have specifically shown that feverfew extracts inhibit the synthesis of many inflammatory compounds at the early stage of synthesis. This reduction of inflammatory agents results in relief from pain due to inflammation.

Dosage and Length of Treatment

The effectiveness of feverfew depends on adequate levels of parthenolide, its principle active ingredient. Commercial preparations vary widely in the amount of parthenolide, and the majority of products contain none, or only trace amounts. The Health Protection Branch suggests a daily dose of 125mg of a dried feverfew leaf preparation containing at least 0.2% parthenolide for the preventative treatment of migraines. Alternatively, 50 to 200mg of the raw herb or 5 to 20 drops of tincture [1:5 (20%) ethanol] can be effective.

The preventative treatment of migraine headaches is recommended if one experiences more than three to four episodes of attacks per month, and more than three months in a row. There is no specific recommendation pertaining to the length of treatment. A four to six month migraine-free period seems to be a reasonable time frame before one decides to stop treatment. Of course, when migraines return, one should carry on a longer period of treatment.

Possible Side Effects

Although adverse effects of feverfew are rare, the main ones to be aware of are mouth ulceration and gastrointestinal upset. Feverfew is not recommended for pregnant women due its ability to induce menstruation. It is also not recommended for treating children because there is still a lack of clinical data around its effect on young people.

Compiled by Gerry Poon
Royal Oak Medicine Centre, Victoria, B.C.
Edited by Megan Stiles
Last Reviewed: September 2001