Herbs & Supplements:
Feverfew
Tanacetum parthenium
Principal Proposed Uses
•
Migraine Headaches (Prevention and Treatment)
Other Proposed Uses
•
Arthritis
Originally native to the Balkans, this relative of the common daisy was spread by deliberate planting throughout Europe and the Americas. Feverfew's feathery and aromatic leaves have long been used medicinally to improve childbirth, promote menstruation, induce abortions, relieve rheumatic pain, and treat severe headaches.
Contrary to popular belief, feverfew is not used for lowering fevers. Actually, "feverfew" is a corruption of the name "featherfoil."1 Featherfoil became featherfew and ultimately feverfew. In a weird historical reversal, this name then led to a widespread belief among herbalists that feverfew could lower fevers. After a while they noticed that it didn't work, and then angrily rejected feverfew as a useless herb! Feverfew remained out of fashion until a serendipitous event occurred in the late 1970s.
At that time, the wife of the chief medical officer of the National Coal Board in England suffered from serious migraine headaches. When workers in the industry learned of this fact, a sympathetic miner suggested she try a folk treatment he had used. She followed his advice and chewed feverfew leaves. The results were dramatic: her migraines disappeared almost completely.
Her husband was impressed, too. He used his high office to gain the ear of a physician who specialized in migraine headaches, Dr. E. Stewart Johnson of the London Migraine Clinic. Johnson subsequently tried feverfew on 10 of his patients. The results were so good that he subsequently gave the herb to 270 of his patients. A whopping 70% reported considerable relief.
Thoroughly excited now, Dr. Johnson enrolled 17 feverfew-using patients in an interesting type of double-blind study: half continued to use feverfew, and the other half were transferred, without their knowledge, to a placebo.2 Over a period of 6 months, the patients withdrawn from feverfew demonstrated a dramatic increase in headaches, nausea, and vomiting.
Unfortunately, this study didn't prove much. It was too small, and because the patients were already feverfew users, it didn't say anything about the effectiveness of feverfew in the population at large. (Presumably, the participants used feverfew because they already knew that the herb worked for them.) Nonetheless, the study brought a flood of response from the public, and ultimately led to the somewhat larger double-blind experiments described below.
For many years, it was assumed that the active ingredient in feverfew was a substance named parthenolide. Numerous articles were published explaining exactly how parthenolide prevented migraines, stating that it caused platelets to release serotonin and reduce the synthesis of prostaglandins, leukotrienes, and thromboxanes.3–6 Based on this premature explanation, indignant authors complained that samples of feverfew on the market varied as much as 10 to 1 in their parthenolide content. No less an authority than herbal expert Varro Tyler said, "Standardization of the herbal material on the basis of its parthenolide content is urgently required if this potentially valuable herb is to be used effectively."7
However, everyone was jumping the gun. A recent study found that an extract of feverfew standardized to a high parthenolide content is entirely ineffective.8 Apparently, this high-parthenolide extract lacked some essential substance or group of substances present in the whole leaf. What those substances may be, however, remains mysterious.
What Is Feverfew Used for Today?
Feverfew is primarily used for prevention of chronic, recurrent migraine headaches. It must be taken religiously every day for best results.
Feverfew is also sometimes used at the onset of a migraine attack. It is not believed to be effective for cluster or tension headaches.
It is important to remember that serious diseases may occasionally first present themselves as migraine-type headaches. For this reason, proper medical diagnosis is essential if you suddenly start having migraines without a previous history, or if the pattern of your migraines changes significantly.
Feverfew is sometimes recommended for various forms of arthritis, but there is no evidence that it works.
What Is the Scientific Evidence for Feverfew?
Three published double-blind studies have been performed to evaluate feverfew's effectiveness as a preventive treatment for migraines. Two returned positive results, the other negative.
The Nottingham trial followed 59 individuals for 8 months.9 For 4 months, half received a daily capsule of powdered feverfew leaf; the other half took placebo. The groups were then switched and followed for an additional 4 months. Treatment with feverfew produced a 24% reduction in the number of migraines and a significant decrease in nausea and vomiting during the headaches.
A subsequent double-blind study of 57 people with migraines found that use of feverfew leaf could decrease the severity of migraine headaches.10 Unfortunately, this trial did not report whether there was any change in the frequency of migraines.
However, a Dutch study involving 50 people showed no difference whatsoever between placebo and a special feverfew extract standardized to parthenolide content.11 As mentioned above, the explanation appears to be that parthenolide is not the active ingredient in feverfew.
An unpublished double-blind placebo-controlled study of 147 individuals found equivocal evidence for feverfew.12 Researchers first measured the number of migraine headaches that participants experienced during a 4-week period of no treatment. Then, for a subsequent 12 weeks, participants received either placebo or one of three doses of a proprietary feverfew extract. Researchers compared the number of migraine attacks during the final 4 weeks of treatment against the number of migraines during the initial 4-week monitoring period.
The results showed no statistically significant benefit overall. However, in a subgroup of individuals with the most frequent migraines, the two higher doses of feverfew extract significantly reduced migraine attacks.
Dosage
Given the recent confusion surrounding parthenolide, previous dosage recommendations for feverfew based on parthenolide content have been cast in doubt. At the present time, the best recommendation is probably to take 80 to 100 mg of powdered whole feverfew leaf daily.
When taken at the onset of a migraine headache, higher amounts of feverfew are often used. However, the optimum dosage has not been determined.
Safety Issues
Among the many thousands of people who use feverfew as a folk medicine in England, there have been no reports of serious toxicity. Animal studies suggest that feverfew is essentially nontoxic.13
In the 8-month Nottingham trial, there were no significant differences in side effects between the treated and control groups.14 There were also no changes in measurements on blood tests and urinalysis.
In a survey involving 300 people, 11.3% reported mouth sores from chewing feverfew leaf, occasionally accompanied by general inflammation of tissues in the mouth.15 A smaller percentage reported mild gastrointestinal distress.16 However, mouth sores do not seem to occur in people who use encapsulated feverfew leaf powder, the usual form.
In view of its use as a folk remedy to promote abortions, feverfew should probably not be taken during pregnancy.
Because feverfew might slightly inhibit the activity of blood-clotting cells known as platelets,17 it should not be combined with strong anticoagulants, such as Coumadin (warfarin) or heparin, except on medical advice. Feverfew might also increase the risk of stomach problems if combined with anti-inflammatory drugs such as aspirin.18,19,20
Safety in young children, pregnant or nursing women, or those with severe kidney or liver disease has not been established.
Interactions You Should Know About
If you are taking Coumadin (warfarin),heparin,aspirin or other nonsteroidal anti-inflammatory drugs: Do not use feverfew except on medical advice.
View References
Last reviewed March 2002 by Medical Review Board
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