The effect of zinc sulphate and placebo was compared in a double-blind trial in 56 patients suffering from acne vulgaris. Serum vitamin A levels were studied in all, before and at the end of therapy, 29 patients received zinc sulphate 600 mg daily and 27 patients received placebo. Patients on placebo showed no improvement. After 12 weeks of treatment with zinc sulphate, 17 patients (58%) showed significant improvement. There was a statistically significant decrease in the number of papules, infiltrates and cysts. In zinc-treated cases there was statistically significant increase in serum vitamin A levels, while no change was found in the placebo group.