Cascara is a shrub or small tree native to the Pacific Coast, from British Columbia to northern California, and to Rocky Mountain regions near the Canada - U.S. border.
Cascara is a shrub or small tree native to the Pacific Coast, from British Columbia to northern California, and to Rocky Mountain regions near the Canada - U.S. border.

© 2005, Coalition of Canadian Healthcare Museums and Archives

Cascara (Rhamnus purshianus)

Missouri Botanical Garden

© Missouri Botanical Garden


First Nations used the yellow inner bark of this tree as a remedy for constipation. Settlers adopted it by the early 1800s. Its use spread around the world until, in the early 1900s, it was the most widely used laxative substance on the planet. In the mid-1900s, demand for cascara began to decline as other products came on the market.
First Nations used the yellow inner bark of this tree as a remedy for constipation. Settlers adopted it by the early 1800s. Its use spread around the world until, in the early 1900s, it was the most widely used laxative substance on the planet. In the mid-1900s, demand for cascara began to decline as other products came on the market.

© 2005, Coalition of Canadian Healthcare Museums and Archives

Cascara is still an ingredient in many over-the-counter laxative products. The chemical compounds it contains have been found to stimulate muscle contractions in the large intestine, but do not affect the small intestine.

There is little new research being done on cascara.

Cascara is still an ingredient in many over-the-counter laxative products. The chemical compounds it contains have been found to stimulate muscle contractions in the large intestine, but do not affect the small intestine.

There is little new research being done on cascara.


© 2005, Coalition of Canadian Healthcare Museums and Archives

Cascara is a small tree - up to 15 metres tall. It is available from native plant nurseries in British Columbia and is becoming more popular as a landscaping tree for its ability to withstand dry summers without special care.
Cascara is a small tree - up to 15 metres tall. It is available from native plant nurseries in British Columbia and is becoming more popular as a landscaping tree for its ability to withstand dry summers without special care.

© 2005, Coalition of Canadian Healthcare Museums and Archives

Cascara bark is collected primarily from the wild. About 5 million pounds of dried bark are gathered in North America each year, and over-harvesting has reduced the number of trees. British Columbia now regulates the harvest. Interest in cultivated production is increasing as wild sources become rarer.
Cascara bark is collected primarily from the wild. About 5 million pounds of dried bark are gathered in North America each year, and over-harvesting has reduced the number of trees. British Columbia now regulates the harvest. Interest in cultivated production is increasing as wild sources become rarer.

© 2005, Coalition of Canadian Healthcare Museums and Archives

A Blessing?



Early Spanish explorers were so impressed by the virtues of Rhamnus purshianus that they named the tree "cascara sagrada" or "holy bark".

Museum of Health Care at Kingston

© Museum of Health Care at Kingston


Learning Objectives

The learner will:
  • describe the plant Cascara;
  • explain why Cascara is interesting as a plant remedy.