Several causes for milk intolerance are known, of which lactose intolerance is only one. Others include a local (e.g. gastrointestinal) toxic effect caused by one or more milk components and an immunological effect due to hypersensitivity to milk protein(s). Recent publications dealing with these phenomona are cited and the need for physicians, especially pediatricians, to become more knowledgeable in this area is emphasized. Methods to diagnose lactose intolerance are discussed, especially their limitations which likely have resulted in recommendations to too many individuals to restrict milk from their diets.