Neonatal hypoglycaemia is a common clinical problem and the traditional treatment for the condition is intravenous glucose administration. The glycaemic effects of two additional treatments were investigated, in a randomised trial, in 23 neonates who were receiving intravenous glucose as treatment for hypoglycaemia. Eleven infants received an intravenous bolus dose of glucagon (200 micrograms/kg) and 12 infants received intragastric medium chain triglyceride (MCT) (5 ml/kg). Blood concentrations of glucose and intermediary metabolites were measured before and one hour after treatment, and, using stable isotope infusion, glucose production rates were calculated. After glucagon, there was a mean rise in blood glucose concentration of 1.6 mmol/l and in the glucose production rate of 2.6 mg/kg/min. After MCT, there was a small mean rise in blood glucose concentration of 0.4 mmol/l, but the effect of MCT on glucose production rate was variable. Intravenous bolus glucagon administration exerted a glycaemic effect which was associated with an increase in glucose production rate. The use of glucagon, as an alternative treatment to intravenous glucose, should be investigated further.