Vitiligo, an acquired, idiopathic leucoderma, has long been a vexing therapeutic problem for the physician. Therapy for this affliction has included use of ultraviolet light, freezing with carbon dioxide snow, injections of gold thiosulfate, topical applications of bergamot oil, administration of pituitary melanocyte-stimulating hormone (MSH), and the systemic and tropical use of the psoralen compounds. We wish to present our experiences with the last-named substances. For many centuries, Egyptians have used the fruit of the Ammi majus Linn, plant in the treatment of vitiligo. A powder was prepared from this plant and ingested with simultaneous exposure of the affected skin to sunlight. While this treatment often produced improvement or a cure, its use not infrequently provoked numerous undesirable side-effects, including erythema and vesiculation of the skin, vomiting, diarrhea, nausea, headache, nephritis, hepatitis, coma, and exfoliative dermititis. In 1947, Fahmy and Abu-Shady isolated from the crude