In 1978 Australian researchers published details of an 'exclusion diet' to exclude specific food chemicals from the diet of patients. This provided a basis for challenge with these additives and natural chemicals. Using this approach the role played by dietary chemical factors in the pathogenesis of chronic idiopathic urticaria (CIU) was first established and set the stage for future DBPCT trials of such substances in food intolerance studies.[64][65]