We have analysed regular drug consumption by Spanish drivers. 675 properly completed questionnaires were received from drivers attending three medical traffic centres in Valladolid (Spain) for medical examination prior to obtaining or renewing of their traffic licence in 1990. Among those surveyed, 28.9% were taking regularly drugs, mainly analgesics (6.5%), antiallergic drugs (5.2%), oral contraceptives (4.6%), anti-inflammatory drugs (4.1%), antihypertensive drugs (3.6%), tranquillizers (3.4%), hypnotics (2.8%) and drugs for rheumatic disorders (2.7%). The study indicates the frequent consumption of drugs by Spanish drivers, and suggests the need to regulate drug consumption by drivers.