It is native to western North America from southern British Columbia south to central California, and eastward to northwestern Montana.

Cascara is a large shrub or small tree 4.5–12 metres (15–39 feet) tall,[2] with a trunk 20–50 centimetres (8–20 in) in diameter.

[4][5] Cascara bark has an intensely bitter flavor that will remain in the mouth for hours, overpowering and even numbing the taste buds.

[2] The flowers are tiny, 3–5 mm (1⁄8–1⁄4 in) diameter, with five greenish yellow petals, forming a cup shape.

[10][11] Cascara is native from northern California to British Columbia and east to the Rocky Mountains in Montana.

[2] Its trees create brushy stands which provide abundant thermal cover and hiding places for wildlife.

[18][19] 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.

[21][22] Laxatives should also not be used by people with Crohn's disease, irritable bowel syndrome, colitis, hemorrhoids, appendicitis, or kidney problems.

[18][20] Cascara is sold in the United States as a natural "dietary supplement" rather than a drug, and its common use is ingested by mouth to relieve constipation.

[18][20] Use of cascara may adversely affect the actions of various prescribed drugs, such as digoxin, warfarin, corticosteroids, and diuretic agents.

[18][20] The dried, aged bark of R. purshiana used by indigenous native cultures and immigrant Euro-Americans as a laxative is similar to other anthraquinone-containing herbal preparations of leaves and fruits of senna, the latex of Aloe vera, and the root of the rhubarb plant.

The food industry sometimes uses cascara as a flavoring agent for liquors, soft drinks, ice cream, and baked goods.