Despite the name "melanosis," the pigment isn't melanin. The Pigment: It is actually lipofuscin, a "wear and tear" pigment. The Process: Anthraquinone laxatives cause apoptosis (cell death) of the colonic epithelial cells. Smoker's melanosis Wikipedia This lovely patient was thrilled with her beautiful result after laser treatment of oral melanotic macules. I share this case to educate: laser treatment requires accurate diagnosis, an understanding of the differential Iris Melanosis in Cats: Causes, Symptoms, and Treatment Cats.com