Cascara

Rhamnus purshiana Rhamnaceae

This evergreen tree is native to the west coast of the USA but is now cultivated in East Africa, where the climate is similarly hot and dry. The cascara grows to a height of 3-12m and has oval, pointed leaves with numerous straight veins. Its fruit is a black poisonous berry with a stone that contains a black seed. The bark is brownish and scattered with whitish pores.

Parts used

Constituents

The active principles in cascara bark are hydroxyanthraquinone glycosides, known as cascarosides, which exert a laxative effect.

Medicinal uses

Cascara bark has a laxative or purgative effect according to how much is taken. These effects are due to the way the plant affects the absorption of water and electrolytes and stimulates contractions within the intestine. Cascara bark is prescribed to treat the symptoms of occasional bouts of constipation and must be taken strictly as prescribed by a doctor or medical herbalist.

Cascara may also be beneficial in the treatment of liver disorders. Studies by Chinese scientists in 2000 found that the glycoside emodin reduced the development of fibrosis in the livers of rats.

PREPARATION AND DOSAGE

Cascara bark can only be used on prescription. Although some cascara products are available commercially, it is advisable to consult a doctor or qualified medical herbalist to avoid aggravating the problem.

IF SYMPTOMS PERSIST, CONSULT A DOCTOR

Cultivation

Propagated by ripe seed, greenwood cuttings or layering, this species should be grown in welldrained soil in sun or light shade.

CAUTIONS