Butterbur can be found growing along rivers, ditches, and marshy areas in northern Asia, Europe, and parts of North America. It sends up stalks of reddish flowers very early in spring, before producing very large heart-shaped leaves with a furry gray underside. Once the leaves appear, butterbur somewhat resembles rhubarb—one of its common names is bog rhubarb. It is also sometimes referred to as "umbrella leaves" due to the size of its foliage. Other more or less descriptive common names abound, including blatterdock, bogshorns, butter-dock, butterly dock, capdockin, flapperdock, and langwort.

Butterbur is often described as possessing an unpleasant smell, but being malodorous hasn't protected it from harvesting by humans. The plant has a long history of use as an anti-spasmodic, thought to be effective for such conditions as stomach cramps, whooping cough, and asthma.

Externally, butterbur has been applied as a poultice over wounds or skin ulcerations.

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What Is Butterbur Used for Today?

A special toxin-free butterbur extract has been investigated for the treatment of a variety of illnesses. Two double-blind trials suggest that this butterbur extract may be useful for preventing migraine headaches]]> . ]]>1,]]>]]>16]]> In addition, meaningful evidence indicates that this extract is helpful for ]]>hay fever]]> . ]]>14,17,18,23,24]]>

There is some evidence that butterbur has anti-inflammatory and anti-spasmodic effects, ]]>2,3]]> and on this basis it has been proposed as a treatment for a variety of ]]>musculoskeletal pain]]> conditions; however, meaningful clinical trials have not been reported. ]]>4,5,6]]> Butterbur has also undergone highly preliminary investigation for treatment of ]]>asthma]]>]]>7,8]]> and for protecting the stomach lining from injury, thereby helping to prevent ]]>ulcers]]> . ]]>9,10]]>

Preliminary evidence suggests that butterbur is not likely to be particularly effective for allergic skin diseases, such as ]]>eczema]]> . ]]>19]]>

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What Is the Scientific Evidence for Butterbur?

Migraines

Two double-blind, placebo-controlled studies suggest that butterbur extract may be helpful for preventing migraines, although the optimum dosage is not clear.

Butterbur extract was tested as a migraine preventive in a double-blind, placebo-controlled]]> study involving 60 men and women who experienced at least three migraines per month. ]]>11]]> After 4 weeks without any conventional medications, participants were randomly assigned to take either 50 mg of butterbur extract or placebo twice daily for 3 months.

The results were positive: both the number of migraine attacks and the total number of days of migraine pain were significantly reduced in the treatment group as compared to the placebo group. Three out of four individuals taking butterbur reported improvement, as compared to only one out of four in the placebo group. No significant side effects were noted.

In another double-blind, placebo-controlled study performed by different researchers, 202 people with migraine headaches received either 50 mg twice daily of butterbur extract, 75 mg twice daily, or placebo. ]]>16]]> Over the 3 months of the study, the frequency of migraine attacks gradually decreased in all three groups. However, the group receiving the higher dose of butterbur extract showed significantly greater improvement than those in the placebo group. The lower dose of butterbur failed to prove significantly more effective than placebo.

Based on these two studies, it does appear that butterbur extract is helpful for preventing migraines, and that 75 mg twice daily is more effective than 50 mg twice daily. However, further research is necessary to establish this with certainty.

Hay Fever (Allergic Rhinitis)

Butterbur appears to affect the immune system in ways that suggest it should be helpful for ]]>hay fever]]> (technically, "seasonal allergic rhinitis"). ]]>15,]]>]]>20]]> On this basis, it has been tested as an allergy treatment, with positive results in substantial studies.

In a 2-week, double-blind, placebo-controlled study of 186 people with intermittent allergic rhinitis, use of butterbur at a dose of three standardized tablets daily, or one tablet daily, reduced allergy symptoms as compared to placebo. ]]>23]]> Significantly greater benefits were seen in the higher-dose group. Such "dose dependency" is generally taken as a confirming sign that a treatment really works.

In another double-blind study, 330 people were given either butterbur extract (one tablet three times daily), the antihistamine fexofenadine (Allegra), or placebo. ]]>25]]> The results showed that butterbur and fexofenadine were equally effective, and both were more effective than placebo.

A previous 2-week, double-blind study of 125 individuals with hay fever compared a standardized butterbur extract against the antihistamine drug certizine. ]]>14]]> According to ratings by both doctors and patients, the two treatments proved about equally effective. Unfortunately, this study did not use a placebo group.

Two much smaller studies produced inconsistent results. ]]>21,]]>]]>22]]>

It's not clear how butterbur might work. Unlike standard antihistamines, it does not appear to reduce reactions on allergy skin tests. ]]>27]]>

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Dosage

The usual dosage of butterbur is 50-75 mg twice daily of a standardized extract that has been processed to remove potentially dangerous chemicals called pyrrolizidine alkaloids (see Safety Issues]]> below).

Warning : Use of any butterbur product that contains pyrrolizidine alkaloids is definitely not recommended.

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Safety Issues

In studies and postmarketing surveillance involving adults and children, burping and other mild gastrointestinal complaints have been the main side effect of butterbur extract. 16, 26,28]]>

Butterbur contains liver-toxic and possibly carcinogenic components called pyrrolizidine alkaloids. ]]>12]]> Fortunately, it is possible to remove these compounds from butterbur products. ]]>13]]> In Germany, the maximum allowable content of pyrrolizidine alkaloids in butterbur products has been set at 1 microgram per daily recommended dose.

Butterbur should not be used by pregnant or nursing women, young children, or people with severe kidney or liver disease, until further safety testing has been performed.