The treatment of vitiligo has been unsatisfactory. Introduction of systemic furocoumarins to treatment regimens has given very promising results. Trimethylpsoralen has been found to be more potent than 8-methoxypsoralen. In cases studied, ultraviolet irradiation of affected sites following topical application of trimethylpsoralen was found to hasten the process of repigmentation. Simultaneous treatment of underlying disease produced a quicker response followed by sustained relief.