The bioregion known to some geographers as Cascadia corresponds to the Pacific Northwest and encompasses Southeast Alaska, British Columbia, Western Alberta and Montana, Idaho, Washington, Oregon and Northern California. It is a unique area that is home to a rich diversity of medicinal herbs and other plants, including Rhamnus purshiana, from which comes one of the more familiar herbs otherwise known as Cascara Sagrada Bark. In the original lingua franca of Cascadia, known as Tsinuk Wawa, or "Chinook Jargon," this Native American herb was called chittam or tsittikum.

Because powdered Cascara Sagrada is really the bark or outer covering of a tree, technically it does not belong under the classification of "herbs," per se, since true natural herbs are actually leaves and blades of grass. Nonetheless, like roots and flowers, bark such as dried Rhamnus purshiana have long had their uses.

Bulk herbs such as Rhammus purshiana are usually harvested in the wild, after which they are dried and aged for a time - usually a year - before they are marketed as wholesale organic herbs. Like other bulk herbs, the effect of Cascara Sagrada bark can be harsh if used in its fresh, undiluted form, so it is best to use aged dried Cascara Sagrada bark.