Natural Products

Crampbark

Scientific names: Viburnum opulus, V. opulus var. americanum

Common names: Cramp bark also is known as guelder rose, snowball, squaw bush, cranberry tree, highbush cranberry, and pimbina.

Efficacy-safety rating:

●...Little or no evidence of efficacy.

Safety rating:

●...Little exposure or very minor concerns.

What is Crampbark?

Viburnum opulus is a large bush that often is grown ornamentally for its attractive white flowers. It is native to northern Asia and Europe. The American variety of V. opulus (also known as V. trilobatum) has edible red berries, while the European variety bears bitter fruit. The trunk and root bark are the commonly used drug products.

What is Crampbark used for?

Traditional/Ethnobotanical uses

The American variety was used by the Iroquois for prolapsed uterus after childbirth, and other tribes recognized its use as a diuretic. The Eclectic medical movement in the 19th century adopted cramp bark for dysmenorrhea and to prevent miscarriage. It was believed to be a stronger antispasmodic than the related Viburnum species V. prunifolium (black haw). The bark was made official in the U.S. Pharmacopeia in 1894 and was included in the National Formulary in 1916. Widespread adulteration by mountain maple (Acer spicatum) and other Viburnum species led to confusion about the correct source plant. A later review surveyed the botanical, chemical, and pharmacological differences between black haw and cramp bark.

Uterine relaxant

Cramp bark has been used for painful menstruation and to prevent miscarriage. Animal studies show that cramp bark relaxes uterine tissues. However, no clinical studies examining efficacy in humans have been performed.