Hereditary fructose intolerance is an autosomal recessive disorder that illustrates vividly the interplay between heredity and environment in the genesis of human nutritional disease. Genetically determined defects of an isozyme of fructose bisphosphate aldolase (aldolase B, which is specialized for the metabolic assimilation of dietary sugars) predispose to this widely distributed condition. Ingestion of fructose, sorbitol, or sucrose induces abdominal pain, vomiting, and metabolic disturbances — including low concentrations of blood glucose — that may prove fatal. The response to dietary exclusion is rapid and, when so treated, the disease is compatible with a normal life span. A noteworthy feature of the condition in individuals who survive the stormy period of weaning is the development of powerful aversions to fruit, nuts, and sweet‐tasting foods and drinks. The incidence of dental caries is consequently much reduced.— Cox, T. M. Aldolase B and fructose intolerance.FASEB J.8: 62‐71; 1994.