Phenobarbitone kinetics was studied in malnourished and normal children after single oral dose of approximately 7.0 mg/kg. Estimation of serum phenobarbitone concentration was performed by spectrophotometric method. Elimination half-life was 58.9 +/- 9.5 h and 30.15 +/- 6.1 h for malnourished and healthy children, respectively. Compared to healthy children, tmax was prolonged in malnutrition group suggesting slow absorption in the latter group. The systemic bioavailability was observed to be higher in protein energy malnutrition. Modifications of the usual dosage regimen in malnutrition are recommended.