Virgil Sydenstricker was a member of a notable American family which included authoress Pearl S. Buck and the eminent epidemiologist Edgar Sydenstricker. Dr. Sydenstricker's contributions in the fields of hematology and nutritional disease are legion. His landmark work in sickle cell anemia characterized a definite symptom complex with specific hematologic findings and inheritance pattern. He wrote on the complications of malnutrition and attempted to delineate the specific effects of individual nutritional factors. Dr. Sydenstricker and his associate H. M. Cleckley first described the syndrome of niacin deficiency encephalopathy. Today, the syndrome is still occasionally reported. Niacin deficiency should be considered when unexplained acute confusional states or neurologic deficits occur in the setting of malnutrition, antituberculous drug use, or chronic partial nutritional deficiency with acute increase in metabolic demand.