Butterbur

(Petasites hybridus and related species)

Butterbur (also known by many other names including western coltsfoot, wild rhubarb etc.) is a perennial shrub that grows in Europe, Asia and North America, usually in marshes, damp woodland and adjacent to rivers or streams.

Butterbur extracts are claimed to be helpful for gastrointestinal pain, rhinitis and lung diseases, and there is also good evidence for migraine relief. The active constituents have been identified as petasin and isopetasin, which appear to reduce smooth muscle spasm and also have an anti-inflammatory effect.

Side effects of butterbur may include indigestion, headache, fatigue, nausea and vomiting, diarrhoea or constipation. Pregnant or nursing women, children, or people with kidney or liver disease should not take butterbur. Butterbur is a member of the ragweed plant family, and anyone having a known allergy to ragweed or to marigold, daisy, or chrysanthemum should not use butterbur.

The raw herb as well as teas, extracts, and capsules made from the raw herb should not be used because they contain pyrrolizidine alkaloids that can be toxic to the liver and kidneys and may also be carcinogenic. These alkaloids can be removed chemically and only extracts which have been treated in this way should be used.