Definition of Melanosis coli

Melanosis coli: A benign, reversible condition usually, but not always, associated with long-term use of anthranoid laxatives in which pigment deposition in the lamina propria of the large intestine results in a brown to black discoloration of the mucosa (lining) of the large intestine. Melanosis coli is sometimes called pseudomelanosis coli since the pigment deposited is lipofuscin and not melanin as the name implies. Melanosis coli produces no symptoms and is indicative of chronic anthranoid (senna) laxative use.