There are increasing challenges for the practising gastroenterologist in treating AIDS-related gastrointestinal diseases. The differential diagnoses of dysphagia and odynophagia include cytomegalovirus (CMV) and herpes simplex virus (HSV) infection, non-specific aphthous ulceration and non-AIDS oesophageal diseases, especially reflux oesophagitis. Chronic subacute abdominal pain with nausea, vomiting, early satiety and weight loss is suggestive of an obstructive lesion caused by lymphoma or Kaposi's sarcoma. Severe acute abdominal pain can indicate pancreatitis or intestinal perforation due to cytomegalovirus. Right upper quadrant pain (with or without fever, vomiting or abnormal liver function tests with a cholestatic profile) is suggestive of hepatobiliary pathology including cholecystitis, cholangitis, acalculous cholecystitis and AIDS cholangiopathy. Diarrhoea is the most common gastrointestinal symptom of AIDS, affecting 50-90% of patients. Causes of AIDS diarrhoea include protozoa (Cryptosporidium parvum, Isospora belli, Enterocytozoon bieneusi, Septata intestinalis, Cyclospora spp, Entamoeba histolytica and Giardia lamblia), bacteria (Mycobacterium avium-intracellulare, Clostridium difficile, Salmonella, Shigella and Campylobacter jejuni), and viruses (CMV, HSV and possibly HIV). Chronic diarrhoea, malnutrition and weight loss can shorten the life-span of patients with AIDS. Elemental diets, isotonic formulas, medium chain triglycerides and total parenteral nutrition have been tried with little success in AIDS patients with severe diarrhoea and wasting.