Drug use before hospital admission was studied prospectively in 284 consecutive patients admitted to general medical wards in Zimbabwe. Drugs were used by 84% of patients. Self-medication was used by 143 (50%) patients, aspirin (54%) and chloroquine (17%) being the most commonly used drugs. Traditional medicines were used by 55 (19%) patients. Drugs dispensed from orthodox medical sources were taken by 128 (45%) patients. Analgesics (22%), antibiotics (18%), and chloroquine (13%) were the commonest drugs dispensed. Urine screening tests were performed and were positive for aspirin in 37% of cases, chloroquine (33%), and antibiotics (20%). Adverse drug reactions requiring hospital admission occurred in 14 patients (10 orthodox medicines, 4 traditional medicines). Drug use before hospital admission, which is often poorly documented, is a source of potential drug toxicity and may obscure a diagnosis of infective illness.