Insufficient drug evaluation in children and the lack of adapted pharmaceutical formulations explain the importance of unlicensed and off-label prescriptions. As a consequence a regulation proposed in the USA by the Food and Drug Administration, requiring manufactures to assess the safety and effectiveness of new drugs in paediatric patients, has recently been adopted. Appropriate means to facilitate drug evaluation in children are now necessary in terms of recruitment and methodology. A ten-centre American Pediatric Pharmacology Research Unit network has been created and is being financed by the National Institute of Health. A similar trend is evolving in Europe. Appropriate drug utilization in children requires adequate formulations, administration devices and information as well as improved knowledge on the long-term potential consequences of drug use during growth and maturation.