Cramp bark (Viburnum opulus) is a deciduous tree or shrub that is native to Europe and the eastern United States. It is a member of the Caprifoliaceae family. It is also cultivated for use as an ornamental tree or shrub. Other names for cramp bark include guelder rose, snowball tree, king's crown, high cranberry, rose elder, water elder, Whitsun rose, May rose, dog rowan tree, Whitsun bosses, silver bells, and gaiter berries.
Cramp bark grows in low grounds, woodlands, thickets, and hedges. This large shrub grows 5-10 ft (1.5-3 m) tall. The flowers, which appear in spring and summer, are large (3-5 in [8-13 cm] across), flat-topped clusters of snow-white florets. The inner florets are very small, complete flowers while the florets along the outer edge of the cluster are large and showy but cannot produce fruit. The fruits, which appear in August, are drooping clusters of bright red oval shiny, translucent berries. Cramp bark berries are edible, but have a very bitter taste. The leaves of cramp bark are lobed and turn a rich purple color in the fall. The bark is grayish-brown, faintly cracked lengthwise, and has scattered brown-colored warts. The bark has a strong odor and a bitter, astringent taste.
Constituents and bioactivities
Cramp bark contains a wide variety of biologically active compounds. The constituents of cramp bark are very similar to those of a close relative called black haw (Viburnum prunifolium). Cramp bark and black haw may be used interchangeably under certain conditions but should not be considered interchangeable in the strict sense. The constituents of cramp bark include:
hydroquinones (arbutin, methylarbutin, and free hydro-quinone)
myricyl alcohol
paeoniside
pectin
protein
resin
tannins (catechin and epicatechin)
viopudial
Cramp bark has antispasmodic (relieves muscle spasms), anti-inflammatory (relieves inflammation), nervine (calms and soothes the nerves), hypotensive (lowers blood pressure), astringent (causes local contraction), emmenagogic (induces menstruation), and sedative (reduces activity and excitement) properties. The berries of cramp bark have antiscorbutic (effective against scurvy) properties due to their vitamin C content.
General use
Historically, the Native American Meskwaki people used cramp bark to treat cramps and pains located anywhere in the body, whereas the Penobscot people used cramp bark to treat mumps and swollen glands. Cramp bark was named for its primary medicinal use—to relieve muscle cramps and other conditions caused by muscle overcontraction.
Cramp bark is presently used to relieve any overly tense muscle or muscle spasm of the body. This includes the muscles of the uterus, air passages, intestines, arms, legs, and back. In addition, it can be used to prevent muscle tension and pain. Cramp bark is also used to treat symptoms that are associated with excess muscle tension, including menstrual pain (dysmenorrhea) caused by uterine muscle contractions, and breathing difficulties associated with asthma. Colic, spastic constipation, irritable bowel syndrome, and the physical indications of nervous tension are also treated with cramp bark.
Cramp bark has also been used to treat hysteria, nervous complaints, debility, convulsions, fits, lockjaw, heart palpitation, tension headaches, spasmodic stricture (narrowing of a passage), bladder muscle spasms, high blood pressure, rheumatism, circulatory problems, and heart disease. It is effective in treating cases of arthritis in which joint pain and weakness have led to severe muscle contractions. Cramp bark relaxes the muscles, allowing improvement in blood circulation that can return normal function to the arthritic joints.
Cramp bark is used to treat excessive blood loss during menstruation and menopause, and to induce menstruation in women with light or delayed periods. A woman may treat dysmenorrhea prophylactically (before symptoms appear) by taking cramp bark the day before painful menstruation is expected. Cramp bark is also used to treat endometriosis and threatened miscarriage.
In addition to its medicinal uses, cramp bark has a few culinary applications. Cramp bark berries have been used to make jelly and alcoholic beverages, and they are used in certain food dishes.
Preparations
The bark of cramp bark is peeled off the tree during the spring and summer months. The bark should be peeled off in strips carefully in order not to kill the tree. The bark is chopped up and dried. Cramp bark can be made into a decoction (a water extract), a tincture (an alcoholic extract), or a lotion. Liquid preparations of cramp bark have a reddish-brown color, a slight odor, and an astringent taste.
The decoction is prepared by adding 2 tsp of the dried bark to 1 cup water. The mixture is brought to a boil, the heat is reduced, and the decoction is simmered gently for 10–15 minutes.
Although the recommended doses of the decoction are variable, it is safe to drink up to three cups daily. The dose of decoction for menstrual pain is 0.5 cup every three hours.
Tinctures are more concentrated and act faster (within 30 minutes) than teas or decoctions. The tincture may be taken for long-term conditions caused by muscular tension such as irritable bowel syndrome. Again, the recommended doses vary somewhat, but up to 8 ml may be taken three times a day. The suggested dose of tincture for irritable bowel syndrome is 0.5 tsp in hot water twice a day. The suggested dose of tincture for menstrual cramps is 1 tsp in water three times a day.
A lotion prepared from cramp bark may be rubbed into the skin to relieve painful muscles.
To relieve cramping and back pain at night, cramp bark may be mixed with lobelia (Lobelia inflata). Cramp bark may also be used with Mexican yam (Dioscorea villosa) for ailments of the gastrointestinal and genitourinary systems.
Precautions
Some sources state that the berries of cramp bark are toxic and should not be eaten.
Side effects
Cramp bark is safe for both short- and long-term use. As of June 2000, there were no indications that cramp bark causes any side effects. Pregnant women and women who are lactating (breast-feeding), however, should not use any herbal medicines without first consulting a physician.
Interactions
As of mid 2000, there were no indications of any interactions between cramp bark and any other drug or herbal medicine.
BOOKS
Chevallier, Andrew. The Encyclopedia of Medicinal Plants. New York: DK Publishing, Inc., 1996.
