© Steven Foster
Parts used and where grown
Cascara is a small to medium-size tree native to the provinces and states of the Pacific coast, including British Columbia, Washington, Oregon, and northern California. The bark of the tree is removed, cut into small pieces, and dried for one year before being used medicinally. Fresh cascara bark has an emetic or vomit-inducing property and therefore is not used.
Cascara has been used in connection with the following conditions (refer to the individual health concern for complete information):
| Science Rating | Health Concerns |
|---|---|
 | Constipation |
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit. | |
Historical or traditional use (may or may not be supported by scientific studies)
Northern California Indians introduced this herb, which they called sacred bark, to 16th century Spanish explorers. As it is much milder in its laxative action than the herb buckthorn, cascara became popular in Europe as a treatment for constipation. Cascara has been an approved treatment for constipation in the U.S. Pharmacopoeia since 1890.1
Active constituents
Cascara bark is high in hydroxyanthraquinone glycosides called cascarosides. Resins, tannins, and lipids make up the bulk of the other bark ingredients. Cascarosides have a cathartic action that induces the large intestine to increase its muscular contraction (peristalsis), resulting in bowel movement.2
How much is usually taken?
Only the dried form of cascara should be used. Capsules providing 20–30 mg of cascarosides per day can be used. However, the smallest amount necessary to maintain soft stool should be used.3 As a tincture, 1/4–1 teaspoon (1–5 ml) per day is generally taken. It is important to drink eight 6-ounce (180 ml) glasses of water throughout the day while using cascara. Cascara should be taken consecutively for no longer than eight to ten days.4
Are there any side effects or interactions?
Women who are pregnant or breast-feeding, and children under the age of 12 should not use cascara without the advice of a physician. People with an intestinal obstruction, Crohn’s disease, appendicitis or abdominal pain should not employ this herb.5 Long-term use or abuse of cascara may result in weakened bowel function. It may also cause a loss of electrolytes (especially the mineral potassium). Loss of potassium can lead to abnormalities of heart function and may augment the action of digitalis-like medications with fatal consequences.
Are there any drug interactions?
Certain medicines may interact with cascara. Refer to drug interactions for a list of those medicines.
References
1. Castleman M. The Healing Herbs. Emmaus, PA: Rodale Press, 1991, 99–100.
2. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 128–30.
3. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 104–5.
4. Bradley PR, ed. British Herbal Compendium, vol 1. Bournemouth, Dorset, UK: British Herbal Medicine Association, 1992, 52–4.
5. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 104–5.
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2006-09-07
