Acute diabetic hyperglycaemic emergencies carry a high mortality in tropical countries. Defining a 'hyperglycaemic emergency' as the perceived need for intravenous insulin and saline, we found a mortality of 15/60 (25%) in a 2-month period at Baragwanath Hospital, Soweto in 1981. Following this a programme of improved diabetes care was organized, involving optimization of insulin regimens, home blood glucose monitoring, patient education and concentration of resources on young insulin-dependent patients. Five years later, in 1986, the survey was repeated over a similar 2-month period. The mortality this time was 5/48 (10%), a significant reduction compared with 1981 (p less than 0.05). In addition, mean admission glycosylated haemoglobin fell from 11.8 +/- 2.4 (+/- SD) to 10.5 +/- 2.3% (p less than 0.05). These improvements were achieved by relatively simple and inexpensive manoeuvres which could be applied elsewhere in developing countries.