Opinion about dosage of digoxin in paediatric patients is divided. Difficulties in assessing the effect and toxicity of the glycoside in this age group could lead to administration of unnecessarily high doses. Current dosage schedules were therefore re-evaluated by use of recent pharmacokinetic information.Dose calculations were made on the basis that therapeutic serum concentrations of digoxin are similar in young and adult patients. Such a concept is supported by observations of the effect of digoxin in paediatric patients at comparatively small doses of the glycoside and by reported relationships between myocardial and serum digoxin concentrations at different ages. It was considered appropriate to achieve an average serum concentration of 2nmol/L. A loading dose by oral administration of 0.025mg/kg to full term neonates (<1 month) and 0.035mg/kg to infants [1 month to 1 (2) years] was calculated to achieve saturation of body stores. This should be followed by a maintenance dose 12h later. On average. oral maintenance treatment in full term neonates would be with a dose of 0.010mg/kg/day and in infants with a dose of 0.015 to 0.025mg/kg/day. Infants appear to be non-homogeneous with regard to body clearance capacity, hence the range in dose recommendation.A comparison of current dose recommendations and literature reports with the above calculations shows that the computed loading doses mean a considerable reduction. The calculated maintenance dose to neonates is also substantially decreased compared with existing regimens, whereas there is good agreement between current practice and calculations concerning maintenance digoxin treatment in infants.The calculated dosage schedule for neonates was applied in a clinical study of 5 patients. The efficacy was judged satisfactory, and serum concentrations were in the upper range of those predicted.We suggest that routinely recommended doses of digoxin to paediatric patients, particularly to neonates, are usually unnecessarily high.