Eighty-five patients with the acquired immunodeficiency syndrome (AIDS) were treated at Fairfield Infectious Diseases Hospital between April 1984 and June 1987. Sixty per cent of patients suffered gastrointestinal symptoms during the period of study, and in a further 15% of patients, abnormalities of the gastrointestinal tract were found incidentally. The principal manifestations were oropharyngeal ulceration, dysphagia/odynophagia, abdominal pain, diarrhoea, gastrointestinal bleeding, and perianal lesions. Opportunistic diseases involving all parts of the gastrointestinal system were encountered, the most prevalent being infections that were caused by Candida spp., cytomegalovirus, Mycobacterium avium-intracellulare and herpes simplex, and Kaposi's sarcoma. Abnormal liver-function test-results were found in 41 patients; most commonly, these were attributable to minor drug reactions, and cytomegalovirus or Myco. avium-intracellulare infection. Only one patient became jaundiced clinically. We conclude that involvement of the gastrointestinal tract is common in patients with AIDS, and that gastrointestinal lesions are an important cause of morbidity and mortality in these patients.