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Frangula purshiana
Also called Bearberry, Bearwood, Chittam Bark, Pursh's Buckthorn, Cascara, Cascara False Buckthorn, Western Buckthorn
Cascara buckthorn is a large shrub or small tree native to western North America, grown mainly in the wild and in woodland gardens. This entry covers the species Frangula purshiana, which is best grown in cool, moist, partly shaded sites.
Frangula purshiana (cascara, cascara buckthorn, cascara sagrada, bearberry, and in Chinook Jargon, chittem stick and chitticum stick; syn. Rhamnus purshiana) is a species of plant in the family Rhamnaceae. It is native to western North America from southern British Columbia south to central California, and eastward to northwestern Montana.
The dried bark of cascara was used as a laxative in folk medicine by the indigenous peoples of the Pacific Northwest, and later worldwide in conventional medicines until 2002.
The fruit and bark contain a bitter chemical making them inedible to humans, although there are contested medicinal uses.
Until 2002, cascara was the principal ingredient in commercial, over-the-counter (OTC) laxatives in North American pharmacies until the U.S. Food and Drug Administration (FDA) issued a final rule banning the use of aloe and cascara as laxative ingredients. Serious adverse effects may occur from using cascara, including dehydration, loss of electrolyte levels (such as potassium, sodium, chloride), heart rhythm irregularities, and muscle weakness. There is also concern for its potential carcinogenicity. Laxatives should also not be used by people with Crohn's disease, irritable bowel syndrome, colitis, hemorrhoids, appendicitis, or kidney problems. Use of cascara is a safety concern for pregnant or breastfeeding women, and for children.
Cascara is native from northern California to British Columbia and east to the Rocky Mountains in Montana. It is often found along streamsides in the mixed deciduous-coniferous forests of valleys, and in moist montane forests. Cascara is common in the understory of bigleaf maple forest, alongside red osier dogwood and red alder.
Text excerpted from the Wikipedia article Frangula purshiana by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
