Patients with HIV infection were studied to assess the efficacy of octreotide, a somatostatin analogue, in the long-term management of refractory diarrhoea. Dosage of subcutaneous octreotide was increased progressively at 48 h intervals from 150 to 300, 750 and 1500 micrograms/day according to response. Twenty-nine patients, 21 with Cryptosporidium enteritis, one with Isospora belli enteritis and seven with no identifiable pathogen were selected for the study; four of these were excluded from the study because of death during the first month (two cases), abdominal pain and acute pancreatitis (one case each). Twenty-five patients were evaluable for response. Ten patients (four with Cryptosporidium enteritis, five without an identifiable pathogen and one with I. belli enteritis) achieved a complete response (40%) and nine cases (all with cryptosporidial enteritis) had a partial response (36%). Patients with higher weight and Karnofsky performance status and non-cryptosporidial enteritis had a better response to treatment. Mean durations of treatment and response were 4.2 +/- 4.2 and 4.4 +/- 4.5 months, respectively. In the absence of specific agents for cryptosporidial enteritis and HIV enteropathy, octreotide was found to be useful in the management of chronic diarrhoea in AIDS patients.