Butterbur may sound like a humble herb, but research is finding it’s powerful enough to spin a few decidedly not-fun health ailments on their heads, offering relief from allergies, migraine headaches and more. 

A shrubby plant that grows in marshlands throughout Europe and parts of North America and Asia, butterbur, known scientifically as Petasites hybridus, features large leaves that were traditionally used to wrap butter. But this functional foliage, along with the plant’s roots and rhizomes, has many uses beyond buffering butter from the heat. 

Butterbur contains a medley of active constituents, namely petasin and isopetasin, that work together to provide a potent anti-inflammatory effect. This explains how butterbur extract, when taken as an oral supplement, may help prevent or remedy a range of niggling health issues, according to numerous studies.

But along with these do-good constituents, unprocessed butterbur also contains pyrrolizidine alkaloids (PAs), which are potentially toxic and have been linked to liver damage and serious illnesses, according to the National Center for Complementary and Alternative Medicine. Although PAs are found throughout the shrub, they’re most highly concentrated in the roots. Therefore, according to the American Botanical Council, most butterbur products are made from plants that have been bred to contain super-low levels of PAs and have then undergone a carbon dioxide–based extraction process to remove whatever scant amounts are still present.   

Here’s a look at butterbur’s best-studied healing potential.

Migraine headaches

If you’ve ever had a migraine, you know you’ll do just about anything to tame the pain—including reaching for pharmaceuticals, even if you otherwise try to avoid them. But according to an article published in the Canadian Medical Association’s journal CMAJ in April 2010, people plagued with chronic migraines can actually increase frequency and severity of headaches by taking curative drugs too often. To minimize medication, migraine specialists often prescribe a prophylactic, or preventative, agent—and butterbur shows great promise in this department.

A study published in Neurology in December 2004 gave 245 people who suffered two to six migraines per month either 75 mg or 50 mg of butterbur or a placebo twice a day for four months. At trial’s end, headache frequency decreased 48 percent among the 75 mg group and 36 percent in the 50 mg sector, while those who took the placebo had only 26 percent fewer instances. A research review in the November 2006 issue of Phytomedicine reported similar findings: Taking 150 mg of butterbur a day for three months reduced incidences of migraines by about 50 percent. What’s more, the only significant adverse event reported in these trials was an increase in belching—hardly a bad tradeoff for pain relief.      

Hay fever

Intermittent allergic rhinitis, aka hayfever, can smack you with sneezing fits, itchy and watery eyes and nasal congestion—and we all know the grog and lethargy that conventional antihistamine medications leave you with in return. Luckily, research shows butterbur may offer a solid natural alternative to popping allergy pills. 

A study of 330 hayfever suffers, published in Phytotherapy Research in June 2005, compared a butterbur leaf extract to common antihistamine fexofenadine and a placebo. Sure enough, butterbur was equally as effective as the drug in reducing symptoms and produced zero side effects (the placebo had negligible effect). A 2004 Swiss study evaluated the same butterbur extract in varying doses against a placebo (no antihistamine this time) and also found that the herb worked wonders in relieving hayfever symptoms, with the higher dose outperforming the lower. Once again, no adverse events were reported. 

Asthma

Although butterbur’s potential as an asthma reliever hasn’t been studied as widely as its effects on migraines and hayfever, small-group trials show it may help with this troublesome condition, at least as a complementary therapy. According to a study published in Clinical and Experimental Allergy in January 2004, asthma sufferers who took 50 mg of butterbur per day while still using their inhalers had significantly fewer markers of inflammation after only one week. Another 2004 study, this one of 80 patients and printed in Alternative Medicine Review, found that taking a butterbur root extract for two months led to fewer and less severe asthma attacks. What’s more, 40 percent of those patients who’d been using asthma medications had decreased their usage by the study’s end.

Like any herb, butterbur may not produce the same effects in every person. And even though all signs point to its being safe for many applications, always consult with your healthcare practitioner before embarking on a new herb regimen.