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 has not 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.

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 painconditions; however, meaningful clinical trials have not been reported.4,5,6 Butterbur has also undergone highly preliminary investigation for treatment of asthma7,8 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