DSC of melanin displays well-defined phase transitions as compared to TG. The homopolymer melanin-a katatype aromatics is thermally stable up to about 31-degrees-C, and loses a unit of indole-5,6-quinone with a release of heat of 120.2 J g-1. A second transition (a broad exotherm) occurs with heat evolution of 42.56 J g-1; then with a heat absorption of 40.39 J g-1, the residual organic mass is converted into gases. From the thermal chemistry of melanin, aspects of the colour-imparting structure and the aetiology of vitiligo have been inferred.