Frangula purshiana

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.