Gastrointestinal food allergies may be defined as clinical syndromes which are characterised by the onset of gastrointestinal symptoms following food ingestion where the underlying mechanism is an immunologically mediated reaction within the gastrointestinal tract. These gastrointestinal symptoms, principally vomiting and diarrhoea, sometimes abdominal colic, may be accompanied by other symptoms outside the alimentary tract. The clinical spectrum of these disorders ranges from acute anaphylaxis (rarely leading to death in infancy) to relatively minor symptoms which are difficult to distinguish from other disorders such as toddler's diarrhoea or psychologic disorders. The same food, e.g. cow's milk, may produce a wide range of clinical manifestations. In the one individual, clinical features may change with age. The incidence of gastrointestinal food allergic disease is greatest in the first year of life and decreases with age. There are, broadly speaking, two categories of clinical syndromes which are related to speed of onset of symptoms: immediate and delayed. Those syndromes which manifest immediately after food ingestion are usually easy to diagnose and specific IgE tests and skin prick tests are frequently positive. Those which have a delayed onset of up to several days are difficult to diagnose, and currently available investigations may be unsatisfactory for routine use. In current clinical practice, gastrointestinal syndromes which can be manifestations of food allergy, may be grouped as follows: 1) immediate syndromes, including anaphylaxis and b) acute vomiting +/- diarrhoea in association with cutaneous and respiratory manifestations; and 2) delayed syndromes, including a) food-sensitive small intestinal enteropathies, b) food-sensitive colitis, c) multiple food allergy +/- enteropathy, and d) infantile colic.(ABSTRACT TRUNCATED AT 250 WORDS)