The Californian Buckthorn (Rhamnus purshianus), known more commonly as Cascara Sagrada, is a nearly-allied shrub growing in the United States, from northern Idaho westward to the Pacific Ocean. The drug prepared from its bark is now more commonly employed than those prepared from the two previously described species. The bark is collected in spring and early summer, when it is easily peeled from the wood, and is dried in the shade. Since, as is the case with R. Frangula, it is considered that the action of the bark becomes milder and less emetic by keeping, matured bark, three years old, is preferred. ---Description---As imported, the bark mostly occurs in quills or incurved pieces of varying lengths and sizes, smooth or nearly so externally, covered with a greyish-white layer, which is usually easily removed, and frequently marked with spots or patches of adherent lichens. Beneath the surface it is violet-brown, reddish-brown or brownish, and internally a pale yellowish-brown and nearly smooth. It has no marked odour, but a nauseous, bitter taste. It is frequently also imported in flattened packets, consisting of small pieces of the bark compressed into a more or less compact mass. For Educational purposes only. This information has not been evaluated by the Food and Drug adminstration. This information is not intended to diagnose, treat, cure, or prevent any disease.