Cascara Sagrada (frangula purshiana)

Native to the Pacific Northwest region of the United States, this deciduous tree is a member of the buckthorn family, bearing dark green, serrated leaves and scarlet berries that ripen to black. Seventeenth-century Spanish explorers named it cascara sagrada (or “sacred bark”), perhaps because of its value to Native Americans as a medicinal plant.

Cascara Sagrada

The most important use of the distinctive reddish gray bark was as a laxative. Settlers to the West learned to make a tea by soaking a piece of the dried bark in cold water overnight. In 1877, the pharmaceutical company Parke-Davis first marketed the herb, and a year later, the company introduced a liquid extract of cascara bark as a treatment for constipation.


Common Names: Cascara Sagrada, Sacred Bark

Description: Deciduous tree or shrub, 5 to 25 feet tall; 2- to 6-inch-long veined leaves with serrated edges; umbels of greenish yellow flowers followed by small scarlet to black berries

Hardiness: To Zone 7

Family: Rhamnaceae

Flowering: Spring

Parts Used: Bark

Range/Habitat: Native to the Pacific Northwestern United States and western Canada; high-altitude forests, thickets, and canyon walls

Medicinal use

The tree’s bark contains a gentle laxative that stimulates contractions of the large intestine, helping to move food through the digestive system. In 2002 the FDA issued a ban on over-the-counter stimulant laxative drug products that contain cascara sagrada. Today, cascara sagrada can be purchased as an herbal supplement.

Caution: Cascara sagrada should not be used by pregnant women, nursing mothers, or young children; tell your health-care provider that you are using this laxative. Overuse of stimulant laxatives such as cascara sagrada and aloe can create a dependency on their use.

Other uses

The bark of cascara sagrada can be used to dye wool various shades of gray, brown, and yellow. The tree’s wood has been used for making fence posts and as fuel.

How to grow it

A shrub or small tree, cascara sagrada grows in moist, fertile soil and full sun to partial shade in Zone 7 and warmer. It can be propagated by seed, layering, or cutting. For medicinal use, harvest the bark in spring or fall. Before use, cure the bark for at least 1 year. Aging is essential because consuming the fresh bark can cause vomiting and intestinal spasms.