The authors report the case of a 34-week preterm newborn weighing 1,545 g receiving a parenteral mixture by a central venous catheter. A mistake in the flow-rate program led to the infusion of 200 ml within 2 h. Coma occurred quickly and the patient showed intracellular dehydration, polyuria, metabolic acidosis, hyperglycemia and hyponatremia. The therapeutic aim was the correction of dehydration and acidosis, as well as the prevention of secondary hypoglycemia. Clinic and biologic symptoms disappeared 6 h later Volumetric infusion pumps need permanent safe and accurate control of volume flow-rate.