A strategy taken in situations where there may be a suspicion of an allergic response to a protein in the feed or an inability to digest dietary protein is to convert the patient to an elemental diet.Elemental formulae have been developed in an attempt to improve tolerance and protein absorption.The latter has been demonstrated in randomized trials,although some studies have also indicated that elemental formulae do not provide benefit even to patients with impaired gastrointestinal function.Elemental formulae have been demonstrated as an effective therapy in human immunodeficiency virus (HIV),however, benefit is sparse and in fact the high osmolality of elemental formulae is often considered a hindrance, particularly in short gut.