General Description

Feverfew (Tanacetum parthenium) is a composite plant cultivated in flower gardens throughout Europe and the United States. The name feverfew is a corruption of the word febrifuge, signifying its fever-dispelling properties.

Chemical Composition

The major active chemicals in the plant have been hypothesized to be sesquiterpene lactones, principally parthenolide. However, many investigators have found evidence of other active constituents, including both lipophilic compounds (like sesquiterpene lactones) and hydrophilic compounds, although their exact identity has not been determined.^1–3 The flowering herb also contains 0.02% to 0.07% volatile oils (L-camphor, L-borneol, terpenes, and miscellaneous esters).^4,5 Various compounds in the volatile oil have shown pharmacologic activity.⁶

History and Folk Use

Feverfew has been used for centuries as a febrifuge and for the treatment of migraines and arthritis. Other historic uses of feverfew have been in the treatment of anemia, earache, dysmenorrhea, dyspepsia, trauma, and intestinal parasites.⁴ It has also been used as an abortifacient and in gardens to control noxious pests (its pyrethrin component is an effective insecticide and herbicide).

Pharmacology

Feverfew has demonstrated some remarkable pharmacologic effects in experimental studies. Extracts of feverfew have been shown to inhibit the synthesis of compounds that promote inflammation, including inflammatory prostaglandins, leukotrienes, and thromboxanes. No adverse effects reported for feverfew mimic those of aspirin or nonsteroidal antiinflammatory drugs (NSAIDs), suggesting that the effects of feverfew are in some way distinct from those of the drugs. Inhibition of phospholipase A₂ is more like the effects of corticosteroids.⁷

Feverfew also has favorable effects on the behavior of blood platelets in vitro,^7,8 including inhibition of platelet aggregation and the secretion of inflammatory and allergic mediators like histamine and serotonin. Parthenolide components also exert a tonic effect on vascular smooth muscle.⁹

The combined effect on smooth muscle and platelets is probably responsible for feverfew’s effect in preventing and treating migraine headaches.

Clinical Applications

Feverfew has been used for centuries to relieve fever, migraines, and arthritis. The only condition with confirmed scientific documentation at present is in the prevention and treatment of migraine headache.

Migraine Headache

Physician John Hill, in his book The Family Herbal (1772), noted, “In the worst headache this herb exceeds whatever else is known.” A 1983 survey found that 70% of 270 migraine sufferers who had eaten feverfew daily for prolonged periods claimed that the herb decreased the frequency and/or intensity of their attacks.¹⁰ Many of these patients had shown no response to orthodox medicines.

Numerous double-blind trials have been conducted on the efficacy of feverfew in migraine patients,^10–15 the results of which have been assessed in three meta-analyses.^16–18 The first two of these concluded that the majority of studies show that feverfew extracts are superior to placebo for decreasing the frequency and severity of migraine headaches, although most of the studies were of relatively low methodologic quality, and efficacy was not proved beyond a reasonable doubt.^14,17 The third meta-analysis concluded that feverfew extracts have not been proved in controlled trials to prevent migraine better than placebo.¹⁸

The highest-quality study among feverfew clinical trials used a granulated ethanol extract of feverfew and found it ineffective compared with placebo, whereas all the other trials used unextracted powdered feverfew. As a result, careful attention must be paid in future studies to the types of products used, and the results of trials using different products should probably not be combined in meta-analyses.

One double-blind, randomized clinical trial compared the effects of a combination of a feverfew extract (100 mg) with riboflavin 400 mg and magnesium 300 mg taken daily with riboflavin 25 mg.¹⁹ The control, riboflavin 25 mg, appeared to be just as active as the combination formula, and the trial showed that combining feverfew and magnesium with riboflavin adds no additional benefits for preventing migraine headaches.

In an open trial, feverfew combined with Salix alba (white willow) extracts, 300 mg of each twice a day, has been shown effective at preventing and reducing the severity of migraine without aura.²⁰ A combination of Zingiber officinale (ginger) and feverfew was effective in an open trial for relieving acute migraine pain.²¹ It is not clear if either extract is superior to feverfew alone, and double-blind randomized trials are necessary.