Index of Herbs

Evidence review

Feverfew for Migraine

Tanacetum parthenium

The short answer

Promising clinical evidence

Possibly, as a daily preventive, and only modestly. In the largest and most rigorous trial, a feverfew extract cut migraine attacks by about 0.6 a month more than placebo, but smaller trials disagreed and Cochrane rates the evidence low quality. Feverfew does not stop an attack already under way, and it can take one to two months or more to judge whether it helps.

7 key studies reviewed

Updated October 12, 2026

Key points

  1. 01

    A preventive, not a painkiller

    Feverfew is taken every day to make attacks less frequent. It has not been shown to stop a migraine once it starts, and EMA says about two months is usually needed to see an effect.

  2. 02

    Small benefit in the best trial

    In 170 analyzed patients, the MIG-99 extract cut attacks from 4.8 a month by 1.9, against 1.3 with placebo, a difference of 0.6. The manufacturer funded the trial.

  3. 03

    Earlier trials disagree

    Three small positive trials (17 to 60 people) contrast with two rigorous trials of 50 and 147 people that found no overall benefit. Cochrane calls the evidence low quality.

  4. 04

    Guidelines are split

    A 2012 US guideline rated the MIG-99 extract probably effective but was retired in 2015. Canada’s 2012 guideline advised against feverfew; EMA accepts only traditional use.

  5. 05

    Allergy, pregnancy, and withdrawal

    Avoid it with daisy-family allergy, in pregnancy or breastfeeding, and under 18. Chewing fresh leaves can cause mouth ulcers, and stopping after long use may bring rebound headaches.

Feverfew may help some people with migraine have slightly fewer attacks when it is taken every day as a preventive, but the benefit is modest and the evidence inconsistent. In the largest and most rigorous trial, a carbon dioxide extract of feverfew called MIG-99 reduced attacks by about 0.6 a month more than a placebo (dummy pill), in people who started with nearly five a month. Smaller, older trials were split, and the 2015 Cochrane review rated the overall evidence low quality. Feverfew is not a rescue treatment: it has not been shown to stop a migraine once it has started, and the European Medicines Agency (EMA) says about two months of daily use is usually needed to see an effect. Nothing here is medical advice.

Migraine is a common condition in which attacks of headache, often throbbing and one-sided, come with nausea or sensitivity to light and sound, and sometimes with warning symptoms called aura. Treatment comes in two kinds: medicines taken during an attack, and preventive treatment taken daily to make attacks less frequent when they are frequent or disabling. Feverfew (Tanacetum parthenium) is a small daisy-family plant with a long history in European herbals for fever and headache; EMA’s assessment report quotes John Hill writing in 1772 that “in the worst headache this herb exceeds whatever else is known.” Modern interest began in the late 1970s, when the British press reported that migraine sufferers in Wales had found relief after taking the leaves for some time, and controlled trials followed in the 1980s. Because some headaches signal something serious, EMA’s feverfew indication applies only after a doctor has excluded serious conditions, and a first diagnosis of migraine should come from a clinician.

This page sets out what each controlled trial tested and found, who paid for the key ones, how guideline bodies and regulators have judged the evidence, what products and doses were studied, how long to allow, and who should avoid feverfew. Results apply to the specific preparations tested, which ranged from fresh and dried leaf to an alcohol extract and the MIG-99 extract, and cannot be assumed for every product on the shelf. Migraine also has well-tested preventive medicines, and feverfew is something to discuss alongside them rather than a replacement for a diagnosis or a treatment plan.

See also

The full feverfew monograph Herbs for Headaches and Migraine

02 The trials

Key studies

The trials and reviews that carry the most weight for this question, with the product and dose each one tested. Results apply to the preparation studied.

  1. Cochrane review, 2015

    Systematic review of 6 double-blind randomized trials

    Who
    561 people with migraine
    What and how much
    Feverfew single-herb preparations: dried leaf, an alcohol extract, and the CO2 extract MIG-99
    How long
    Literature searched to January 2015

    Trials too varied to pool. The largest showed 0.6 fewer attacks a month than placebo; three small trials were positive and two rigorous ones (50 and 147 people) found no difference. Low quality evidence; only mild, transient side effects.

  2. Diener et al., 2005

    Randomized, double-blind, placebo-controlled, multicenter

    Who
    218 adults randomized; 170 with confirmed migraine analyzed for efficacy
    What and how much
    MIG-99 feverfew CO2 extract, 6.25 mg three times daily
    How long
    16 weeks

    Attacks fell from 4.8 a month by 1.9 with MIG-99 and by 1.3 with placebo (p = 0.0456); 30.3% versus 17.3% had attacks at least halved. Supported by a grant from the manufacturer, Schaper & Brümmer.

  3. Pfaffenrath et al., 2002

    Randomized, double-blind, placebo-controlled dose-finding trial

    Who
    147 adults with migraine
    What and how much
    MIG-99 at 2.08, 6.25, or 18.75 mg three times daily
    How long
    12 weeks

    No significant benefit overall. In a predefined subgroup of 49 with at least four attacks a month, 6.25 mg cut attacks by 1.8 a month versus 0.3 on placebo (p = 0.02).

  4. Murphy et al., 1988

    Randomized, double-blind, placebo-controlled crossover

    Who
    72 volunteers randomized; 59 with full data
    What and how much
    One capsule of dried feverfew leaf daily (mean 82 mg)
    How long
    4 months on each treatment

    Fewer attacks (3.6 versus 4.7 per two months) and less vomiting with feverfew; attack length unchanged; no serious side effects.

  5. De Weerdt et al., 1996

    Randomized, double-blind, placebo-controlled crossover

    Who
    50 people who had never used feverfew; 44 completed
    What and how much
    Alcohol extract providing 0.5 mg parthenolide daily
    How long
    9 months in total

    Both treatment periods had the same number of migraine attacks; no preventive effect was shown.

  6. Johnson et al., 1985

    Randomized, double-blind, placebo-controlled withdrawal trial

    Who
    17 people already eating fresh feverfew leaves daily
    What and how much
    Freeze-dried feverfew leaf, 25 mg capsules twice daily, or placebo
    How long
    Six 4-week periods

    Those switched to placebo had significantly more frequent and severe headache, nausea, and vomiting; those kept on feverfew stayed stable.

  7. Cady et al., 2011

    Randomized, double-blind, placebo-controlled pilot (acute treatment)

    Who
    60 adults; 208 evaluable attacks
    What and how much
    Sublingual feverfew and ginger (LipiGesic M), taken at the first sign of mild headache
    How long
    1 month

    Pain-free at 2 hours in 32% versus 16% on placebo (p = .02). A combination, not feverfew alone; funded by the maker, PuraMed BioScience.

03 Evidence

What the research shows

Promising clinical evidence

Our rating for Feverfew for Migraine, based on the studies below.

The first controlled trials came from Britain. Johnson and colleagues (BMJ 1985), at the City of London Migraine Clinic, studied 17 people who were already eating fresh feverfew leaves every day. Eight were given capsules of freeze-dried feverfew and nine were switched to placebo for six four-week periods; those on placebo had a significant increase in the frequency and severity of headache, nausea, and vomiting, while the feverfew group stayed stable. That design tests what happens when established users stop, not whether feverfew helps newcomers. Murphy, Heptinstall, and Mitchell (Lancet 1988) gave 72 volunteers a month of single-blind placebo, then one capsule of dried feverfew leaf a day or placebo for four months each in a crossover design (everyone took both, in random order); 60 finished and 59 provided full data. As summarized by EMA, people averaged 3.6 attacks per two months on feverfew against 4.7 on placebo, and vomiting was less common, although attacks lasted just as long. Palevitch and colleagues (Phytotherapy Research 1997) reported less severe attacks with 100 mg of powdered leaf a day in 57 patients. EMA’s assessors note that the crossover trials had no washout period between treatments and that the Palevitch trial did not specify how migraine was diagnosed.

Trials that recruited people new to feverfew were less encouraging. De Weerdt and colleagues (Phytomedicine 1996) gave 50 patients who had never used feverfew a daily capsule of an alcohol extract providing 0.5 mg of parthenolide, the best-known active compound, or placebo in a crossover design; 44 completed the nine-month study, and attacks were no fewer on feverfew. The authors suggested the earlier positive trials had enrolled people who already had good experiences with the herb. The German company Schaper & Brümmer then developed MIG-99, a stable extract made with supercritical carbon dioxide. In a dose-finding trial, Pfaffenrath and colleagues (Cephalalgia 2002) gave 147 patients 2.08, 6.25, or 18.75 mg of MIG-99 three times a day or placebo for 12 weeks and found no significant benefit overall. Only in a predefined subgroup of 49 people with at least four attacks a month did attacks fall with dose, most with 6.25 mg (1.8 fewer a month against 0.3 on placebo), and the authors said this needed confirming in more patients. The paper states that the randomization code was generated on the order of Schaper & Brümmer. A combination of riboflavin, magnesium, and 100 mg of feverfew also did no better than low-dose riboflavin used as a placebo, with 42% versus 44% of 49 completers having their attacks halved (Maizels and colleagues, Headache 2004).

The trial that shifted opinion was by Diener and colleagues (Cephalalgia 2005). Between 1999 and 2002, 14 centers in Germany and France randomized 218 adults aged 18 to 65 who had four to six attacks during a four-week baseline to MIG-99 6.25 mg or placebo three times a day for 16 weeks. Forty-five turned out not to meet all the diagnostic criteria for migraine and were excluded before the treatment code was opened, leaving 170 in the efficacy analysis. Attacks fell from 4.8 a month to 2.9 with MIG-99 and to 3.5 with placebo (reductions of 1.9 and 1.3; p = 0.0456), 30.3% versus 17.3% of patients had their attacks at least halved, and migraine days fell more with feverfew. Nausea, vomiting, sensitivity to light and sound, and attack duration did not differ significantly. The paper states that the design, conduct, and data analysis were supported by a grant from Schaper & Brümmer, the manufacturer of MIG-99, that the design was developed jointly with the company, and that two of the five authors were based there. EMA’s assessors add that patients could take painkillers for attacks during the trial but that the amounts used were not reported.

Independent reviewers remain cautious. The 2015 Cochrane review by Wider, Pittler, and Ernst, whose authors declared no conflicts of interest, included six double-blind trials with 561 participants but could not pool them because the participants, products, and outcome measures differed too much. It concluded that the Diener trial adds some positive evidence, a difference of 0.6 attacks a month, but that this is low quality evidence needing confirmation in larger rigorous trials with stable extracts; the three positive earlier trials were small (17 to 60 participants), and the two rigorous ones (50 and 147) found no difference. A 2020 systematic review of herbal migraine treatments by Lopresti and colleagues (Phytotherapy Research) called the feverfew findings mixed, and NCCIH, citing it, notes that its seven feverfew studies (634 participants) were small and used different sources and doses. A 2025 meta-analysis by Nelaturi and colleagues (Natural Product Research) pooled nine trials with 899 participants and reported a significant fall in attack frequency but no effect on nausea, vomiting, or sensitivity to light and sound, while acknowledging that bias in the trials limited the quality of the evidence.

Guideline bodies have disagreed. The 2012 American Academy of Neurology (AAN) and American Headache Society guideline (Holland and colleagues, Neurology) rated MIG-99 “probably effective” (Level B) for preventing episodic migraine, based on one Class I study, one positive Class II study, and one underpowered negative one, and listed headache rebound after stopping feverfew among the risks of complementary treatments. The AAN retired that guideline on September 16, 2015, because of safety concerns about butterbur, so its ratings are no longer endorsed. According to NCCIH’s clinician summary, the Canadian Headache Society’s 2012 guideline made a strong recommendation, based on moderate quality evidence, not to offer feverfew, while the European Federation of Neurological Societies called it possibly beneficial. The UK’s NICE headache guideline, last updated in 2025, suggests propranolol, topiramate, or amitriptyline for prevention and mentions the supplement riboflavin, but not feverfew. EMA’s herbal committee accepts powdered feverfew only as a traditional herbal medicine, judging the trials too small and low in quality to support well-established use. Open questions include which constituents matter (the parthenolide-standardized extract in the De Weerdt trial failed, and parthenolide could not be detected in the blood of cancer patients given up to 4 mg a day in an early-phase study cited by EMA), whether powdered leaf works like MIG-99, and how feverfew compares with standard preventive drugs; we found no trial comparing them directly.

04 In practice

How it was taken in studies

The trials tested quite different preparations. Johnson’s patients took two 25 mg capsules of freeze-dried leaf a day, chosen because they had been eating about 2.44 fresh leaves (roughly 60 mg) daily; Murphy’s capsules held on average 82 mg of dried leaf; Palevitch used 100 mg of powdered leaf a day; De Weerdt used an alcohol extract providing 0.5 mg of parthenolide a day; and the two German trials used the MIG-99 extract at 6.25 mg three times a day, each dose containing 0.5 mg of parthenolide. EMA’s monograph, which covers powdered feverfew herb taken by mouth in solid forms by adults, gives 100 mg once daily or 200 mg three times daily (100 to 600 mg a day), noting that 100 mg a day may be increased gradually until an effect is obtained. Leaf and extract doses are not interchangeable, and a result for MIG-99 cannot simply be transferred to a powdered-leaf capsule or the other way round. Product strength also varies: in an analysis cited by EMA, capsules holding 25 to 500 mg of leaf matched their labels for leaf content, but parthenolide per capsule varied 150-fold, from 0.02 to 3.0 mg.

Feverfew is meant to be taken every day to make attacks less frequent, not swallowed when a headache begins. In the Diener trial the effect began after one month, reached its maximum after two, and held for the four months studied. EMA’s monograph treats two months as the usual period needed to obtain an effect and advises consulting a doctor if migraines still recur after that or if symptoms worsen; its assessors suggest continuing for two to three months to judge. A headache diary recording attack days, severity, and painkiller use before and during treatment is the practical way to tell whether it is helping, because migraine naturally varies and placebo responses are substantial; the Diener authors cite placebo reductions of 11 to 36% in prevention trials. A different approach has been tested for attacks themselves. Cady and colleagues (Headache 2011) gave 60 people a sublingual (dissolved under the tongue) feverfew and ginger product, LipiGesic M, or placebo at the first sign of a mild headache, and 32% versus 16% were pain-free at two hours. That pilot was funded by the maker, PuraMed BioScience, whose chief executive was a co-author; it tested a combination rather than feverfew alone and enrolled people whose attacks usually start mildly.

Kitchen and folk use differs from what was tested. Chewing fresh leaves, the habit behind the modern revival, is the route most linked to mouth ulcers, and EMA’s assessment report notes that the local mouth reaction may be avoided by using encapsulated products. None of the trials described here tested feverfew tea, and the dose in a cup is unknown. If you decide to stop after months of use, reducing the dose gradually is a sensible precaution given reports of rebound headaches, although tapering itself has not been studied.

05 Caution

Before you try feverfew

Feverfew was generally well tolerated in trials. Cochrane found only mild and transient adverse events, most commonly digestive complaints and mouth ulcers, and EMA notes that three trials reported more adverse events on placebo than on feverfew. In the Diener trial, side effects possibly related to treatment affected 8.4% of people on MIG-99 and 10.2% on placebo. Fresh leaves are different: in a 1983 survey of 300 feverfew users cited by EMA, 11.3% reported mouth ulcers from chewing them, and chewing can also inflame the mouth and tongue, swell the lips, and occasionally dull taste. In the feverfew and ginger trial, numbness in the mouth and nausea were the most common side effects. Handling the plant or using skin products containing it can cause allergic contact dermatitis. Stopping after long use may bring post-feverfew syndrome: in Johnson’s 1985 trial, roughly 10% of people switched to placebo after taking feverfew for several years developed rebound migraine, anxiety, poor sleep, and muscle and joint stiffness. EMA stresses that this was seen in a very small study and not confirmed in larger ones, but still lists rebound symptoms in its safety conclusions.

Do not take feverfew if you are allergic to it or to other plants of the daisy family (Asteraceae, also called Compositae), a contraindication in EMA’s monograph. NCCIH warns that people sensitive to ragweed may react, Memorial Sloan Kettering Cancer Center adds chrysanthemums and marigolds, and EMA’s assessment report notes cross-reactions with tansy, yarrow, marguerite, and aster. Feverfew is not recommended in pregnancy: NCCIH says it may affect uterine contractions, it has a traditional reputation for bringing on menstruation (an emmenagogue), and in a rat study a dose about 11 times the maximum human daily dose was linked to harm to mothers and embryos, though EMA judged that study inconclusive. Little is known about breastfeeding, and EMA does not recommend feverfew then either. It is not recommended under 18 because of a lack of data, and migraine in children and teenagers should be assessed by a doctor. People with a bleeding disorder or planned surgery should check with their doctor first; NCCIH advises stopping feverfew at least two weeks before scheduled surgery.

The bleeding concern rests on laboratory findings and case reports rather than trials. Feverfew extracts inhibit platelet aggregation and secretion in the test tube (Heptinstall and colleagues, Lancet 1985), and NCCIH says feverfew may slow blood clotting, but EMA’s assessment report describes the risks with aspirin, dipyridamole, anticoagulants, heparins, and other antiplatelet drugs as theoretical, because no clinical interaction studies have been done. Two serious reports in the EU safety database stand out: a man on warfarin who also took vitamin E, ginkgo, and feverfew, whose INR (a blood-clotting measure) rose to 27.9 and who died, where missing information made causality impossible to assess; and beta-blocker toxicity, with low blood pressure and a slow heart rate, in a person taking propranolol with feverfew, rated a possible interaction. Propranolol is itself a standard migraine preventive. Memorial Sloan Kettering records a case of altered clotting tests and vaginal bleeding in a woman taking feverfew and notes that feverfew inhibits several drug-metabolizing liver enzymes in the laboratory, with unknown clinical relevance. If you take an anticoagulant, an antiplatelet drug, regular NSAIDs, propranolol, or another prescribed migraine medicine, talk to your doctor or pharmacist before adding feverfew, and avoid combining it with other supplements that may affect clotting, such as ginkgo, without advice.

Some headaches need a doctor, not a herb. The UK National Health Service (NHS) advises calling emergency services for a headache that starts suddenly and is extremely painful, or that comes with a seizure, numbness or weakness, difficulty speaking, walking, or balancing, confusion or drowsiness, loss of vision, a head injury in the past three months, a rash that does not fade under a glass, or a very high temperature with a stiff neck. It advises an urgent appointment for headache with jaw pain when eating or a sore, tender scalp, possible signs of giant cell arteritis (inflamed arteries), and for headache triggered by coughing, sneezing, bending, or exercise. NICE also asks clinicians to assess any substantial change in the character of a person’s headaches. Frequent painkiller use can itself keep headaches going: NICE warns of medication overuse headache in people taking triptans, opioids, or combination painkillers on 10 or more days a month, or paracetamol (acetaminophen), aspirin, or NSAIDs on 15 or more days a month, for three months or more. It is treated by stopping the overused medicines under medical guidance, and feverfew is not a substitute for that.

06 Questions

Frequently Asked Questions

It may help some people a little. In the largest trial, a feverfew extract taken daily for 16 weeks cut attacks by 1.9 a month, against 1.3 with placebo, a difference of about 0.6 attacks. Older trials were split, and the 2015 Cochrane review rated the evidence low quality. Europe’s herbal committee accepts feverfew only as a traditional remedy for preventing migraine. Prescribed preventive medicines have stronger evidence, and butterbur, another herbal option, carries a liver warning.

Feverfew on its own has been tested as a daily preventive, not as a treatment for an attack in progress. The one placebo-controlled trial for attacks tested a product combining feverfew and ginger, dissolved under the tongue at the first sign of a mild headache: 32% of users were pain-free at two hours, against 16% on placebo. It was a 60-person pilot funded by the manufacturer, so the result needs confirming. Use the attack treatment your doctor recommends.

Expect to wait. In the largest trial, the benefit began after about one month and peaked after two. The European Medicines Agency says two months is the usual time needed to see an effect, and its assessors suggest allowing two to three months before judging. Keep a headache diary of attack days and painkiller use before and during treatment. If migraines still recur after two months, or get worse, the agency advises seeing a doctor.

Doses in studies depended on the product. Older British trials used about 50 to 82 mg of dried leaf a day, and the German trials used 6.25 mg of a carbon dioxide extract called MIG-99 three times a day. The European Medicines Agency’s traditional-use monograph gives 100 mg of powdered herb once daily for adults, increased gradually if needed to no more than 600 mg a day. Leaf and extract doses are not interchangeable, and parthenolide content varies widely between brands.

Caution is needed. Feverfew inhibits platelets in the laboratory and may slow blood clotting, though no clinical interaction studies exist. Europe’s safety database holds a fatal case of a very high INR in a man on warfarin who also took feverfew, ginkgo, and vitamin E, where the cause could not be assessed, and a possible interaction with propranolol, a common migraine preventive. Check with your doctor or pharmacist first if you take anticoagulants, antiplatelet drugs, regular NSAIDs, or prescribed migraine medicines.

Rebound symptoms have been reported. In a small 1985 trial, about 10% of long-term users who were switched to placebo developed what became known as post-feverfew syndrome: returning migraines, anxiety, poor sleep, and stiff muscles and joints. Larger trials have not confirmed it, but the 2012 US neurology guideline and the European Medicines Agency both mention rebound symptoms. If you have taken feverfew for months, consider reducing the dose gradually and keep tracking your headaches.

07 References

Sources

These references support the claims on this page. They are not an endorsement of any product. The feverfew monograph carries its own full source list.

  1. Feverfew for preventing migraine

    Cochrane Database of Systematic Reviews (PubMed 25892430), 2015

    Wider, Pittler, and Ernst: six double-blind RCTs, 561 patients, not poolable; Diener trial (n = 218) showed 0.6 fewer attacks a month than placebo; three small positive and two rigorous null trials; low quality evidence; mild, transient adverse events; no author conflicts.

  2. Efficacy and safety of 6.25 mg t.i.d. feverfew CO2-extract (MIG-99) in migraine prevention: a randomized, double-blind, multicentre, placebo-controlled study

    Cephalalgia (PubMed 16232154), 2005

    Diener et al.: 218 randomized, 170 in efficacy analysis; attacks fell from 4.76 by 1.9 versus 1.3 (p = 0.0456); responders 30.3% versus 17.3%; effect from month one, maximal at two; grant from manufacturer Schaper & Brümmer (full text).

  3. The efficacy and safety of Tanacetum parthenium (feverfew) in migraine prophylaxis: a double-blind, multicentre, randomized placebo-controlled dose-response study

    Cephalalgia (PubMed 12230594), 2002

    Pfaffenrath et al.: 147 patients, MIG-99 2.08, 6.25, or 18.75 mg three times daily for 12 weeks; no overall effect; subgroup of 49 improved, 6.25 mg −1.8 versus −0.3 attacks (p = 0.02); adverse events similar to placebo.

  4. Randomised double-blind placebo-controlled trial of feverfew in migraine prevention

    Lancet (PubMed 2899663), 1988

    Murphy, Heptinstall, and Mitchell: 72 randomized to dried feverfew leaf or placebo for four months each in a crossover; 59 analyzed; fewer and less severe attacks and less vomiting; attack duration unchanged; no serious side effects.

  5. A double-blind placebo-controlled pilot study of sublingual feverfew and ginger (LipiGesic M) in the treatment of migraine

    Headache (PubMed 21631494), 2011

    Cady et al.: 60 patients randomized 3:1; pain-free at 2 hours 32% versus 16%, relief 63% versus 39%; oral numbness and nausea most common; funded by PuraMed BioScience, whose CEO was a co-author.

  6. Evidence-based guideline update: NSAIDs and other complementary treatments for episodic migraine prevention in adults

    Neurology (PubMed 22529203), 2012

    Holland et al. for the AAN and AHS: MIG-99 (feverfew) probably effective, Level B, based on one Class I, one positive Class II, and one underpowered negative Class II study; mentions headache rebound on stopping feverfew.

  7. Update: NSAIDs and Other Complementary Treatments for Episodic Migraine Prevention in Adults

    American Academy of Neurology, 2015

    States that the April 2012 guideline is retired, by the AAN Institute Board of Directors on September 16, 2015.

  8. European Union herbal monograph on Tanacetum parthenium (L.) Schultz Bip., herba (Revision 1)

    European Medicines Agency (EMA/HMPC/48715/2017), 2020

    Traditional use of powdered herb for migraine prophylaxis after serious conditions are excluded; 100–600 mg daily; two months usual to see an effect; Asteraceae contraindication; not under 18 or in pregnancy or lactation; interactions none reported.

  9. Assessment report on Tanacetum parthenium (L.) Schultz Bip., herba (Revision 1)

    European Medicines Agency (EMA/HMPC/48716/2017), 2020

    Trial details and critiques (no washout, unreported analgesic use); evidence too weak for well-established use; mouth ulcers in 11.3% of leaf chewers; post-feverfew syndrome; theoretical bleeding risks; warfarin and propranolol reports; 150-fold parthenolide variation.

  10. Feverfew

    National Center for Complementary and Integrative Health (NIH), 2025

    Mixed migraine evidence, citing a 2020 review of 7 studies with 634 participants; mouth sores from fresh leaves; ragweed allergy; may slow clotting, stop 2 weeks before surgery; may affect uterine contractions; little known in breastfeeding.

  11. Headaches and Complementary Health Approaches: What the Science Says

    National Center for Complementary and Integrative Health (NIH), 2025

    Clinician digest: Canadian Headache Society strong recommendation not to offer feverfew; AAN/AHS probably effective; EFNS possibly beneficial.

  12. Feverfew

    Memorial Sloan Kettering Cancer Center, About Herbs, 2024

    Compositae cross-sensitivity including chrysanthemums and marigolds; post-feverfew syndrome; altered coagulation and vaginal bleeding case report; laboratory CYP450 inhibition and antiplatelet effects of unknown clinical relevance.

  13. Headaches in over 12s: diagnosis and management (CG150)

    National Institute for Health and Care Excellence (NICE), 2025

    Warning features needing assessment; medication overuse headache thresholds (10 or 15 days a month for 3 months); prevention with propranolol, topiramate, or amitriptyline and riboflavin; no mention of feverfew.

  14. Headaches

    NHS (UK National Health Service), 2024

    When to call emergency services or seek urgent care for headache, including sudden severe pain, neurological symptoms, stiff neck with high temperature, and jaw pain or tender scalp.

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