When compared with the normal population, patients with vitiligo often showed diminished blood levels of folic acid. In a group of fifteen patients with vitiligo, folic acid levels were below normal in the serum of eleven patients, in the whole blood of five patients, and in the erythrocytes of six patients. Vitamin B12 serum levels were below normal in five of the fifteen patients. Ascorbic acid plasma levels were also lowered in four of the patients. In eight patients prolonged oral administration of folic acid with simultaneous parenteral treatment with vitamin B12 and oral ascorbic acid was followed by definite repigmentation without side effects.