Whenever gastrointestinal function is impaired, the clinical problem of drug absorption and disposition has to be considered, if a rational therapeutic scheme has to be followed. In four infants with a very severe form of coeliac disease a complete analysis of diazepam /DZ/ kinetic was performed, both during the active stage of the disease and after a prolonged period of gluten free diet. With the informed consent of the parents, serial blood samples were drawn during the first 24 hours after single oral administration of 0.3 mg/kg b.w. of DZ, to measure DZ and demethyl-DZ plasma concentration. Urine were collected for 72 hours, to determine free and conjugated metabolites excretion. Much higher peak concentration values of DZ were observed during active stage of the disease together with a smaller volume of distribution. No significant variations of drug absorption were noticed. The relative importance of deep variations of body composition in malnourished coeliac infants and of impaired rate of drug metabolism will be evalutated.