Cascara (Rhamnus purshiana), often called cascara sagrada, is a deciduous shrub or small tree in the Rhamnaceae family. Native to western North America, especially the Pacific Northwest, it bears smooth bark, oval leaves, and dark berries. The bark is the traditional plant part used in herbal preparations.
In traditional western herbal practice, aged cascara bark has been used in formulas associated with bowel regularity. It has typically been prepared only after proper aging or processing, as fresh bark is known to be far more irritating.
Because the bark is a strong herb with a specific traditional role, cascara is not usually treated as a casual household herb and should be approached carefully.

