Acne vulgaris is the most common disease of the skin. Obesity is arguably the commonest of a clinical entities In the affluent society. The pathogenesis of these disorders is far from dear cut and they appear to have little in common. In the present paper it is hypothesized that the pathogenesis of both acne vislgaris and obesity is largely due to a relative deficiency of tlw same agent, pantothenic acid, a vitamin that is hitherto quite unknown to cause any deficiency syndromes in man. Furthermore, the evidence suggests that surprisingly large doses of pantothenic acid are required to overcome deficiency states as illustrated in the treatment of acne vulgaris and weight reduction.