Of 3813 children admitted to the paediatric teaching unit in Mubarak Hospital during 1985, 716 (19%) received either therapeutic (672) or prophylactic (44) antibiotics. The indications were respiratory infections (400), urinary infections (78), septicaemia (58), meningitis (42), gastroenteritis (32), other infections (62) and prophylaxis in rheumatic fever or splenectomy (44). Penicillins were prescribed in 553 children, ampicillins being the most frequently prescribed drugs (295, 41%). Antibiotic use was assessed as unnecessary in 282 children, of whom 203 (72%) had respiratory infections. Overall mistakes were encountered in 352 cases, of which 238 (68%) were in respiratory infections and 302 (86%) involved a penicillin, single or in combination. Mistakes were also commoner with combination than with single antibiotic therapy (66% and 44%, respectively). A departmental policy for the use of antibiotics in gastro-enteritis led to their prescription in only 4% of cases. A written justification for cefotaxime reduced its use by 90%. The lack of similar policies for antibiotic use in respiratory infections leads to high rates of antibiotic use and misuse, probably world-wide.