As a muscle relaxant, it also affects other organs, including the intestines and the skeletal muscles. Cramp bark is considered the most potent uterine antispasmodic of the various Viburnum species because it contains more of the antispasmodic constituent scopoletin.
Cramp bark is perhaps most thought of as a women’s herb for helping with painful menstruation. There are lots of other traditional uses that show it has a general effect on spasm and tension elsewhere in the body. For example, Cramp bark has been historically used for migraine, asthma, biliary colic (from gall stones), renal colic (from kidney stones), and numerous different kinds of indigestion or bowel disturbances where cramp is the key feature.
Cramp bark has been used to halt contractions during premature labour. It has also been used in the last trimester of pregnancy to build up uterine muscles and ensure an easy labour.
The antispasmodic constituents in cramp bark also may lower blood pressure by relaxing vessel walls. When taken in large dosages, cramp bark may reduce leg cramps, muscle spasms, or pain from a stiff neck.