Rhamnus purshiana is a species of buckthorn
Cascara sagrada is an herbal remedy that used to be a common ingredient in some over-the-counter (OTC) laxatives.
The bark comes from a tree called the California buckthorn. This tree grows on the West Coast of the United States and parts of South America. Historically, it was used by Native Americans to treat a host of issues, including:
- digestive problems
- joint and muscle pain