According to studies, "Cascara Sagrada is part of a class that is known as anthracine laxatives. There have been tests done that show some individuals using this class of laxative may develop a condition called melanosis coli. Melanosis coli is a medical term that describes a change in the color of the lining of the colon. In melanosis coli, a layer of cells in the bowel accumulate a pigment that changes the color of the lining from pink to brown or black. It is considered to be a totally benign condition which does not damage the bowel, promote cancer growth, or cause harm or injury. However, approximately 25% of the cases of melanosis coli occur in people without a history of laxative use.