Acne vulgaris has long been accepted as a cutaneous disease of multiple etiologic background. It resists the tendency to compress it into the single cause categories so popular in the past three decades of medical progress. The clinical picture itself defies one track analysis, for the seborrheic factor, the metabolic factor recently emphasized by Bloch,1the pyogenic and acne bacillus elements in the bacteriology and the occasional reference to constitutional underlying dysfunctions, such as Knowles and Decker's2observations on gastric anacidity and Sutton's3on the influence of liver extract, all suggest that the background of acne is a complex. Some years of observation led one of us to the belief that familial and perhaps hereditary predisposition plays a part in this complex background. We were led therefore to survey a series of 143 private records of patients with acne vulgaris, of which the more recent ones