Intranasal administration of glucagon, 1 mg, plus sodium glycocholate 15 mg as a surfactant, raised blood glucose levels and plasma levels of immunoreactive glucagon (IRG) and immunoreactive insulin (IRI). Spray solutions were more effective than drops, and neither the surfactant alone nor glucagon alone had any effect. Blood glucose levels were similarly affected by intravenous glucagon, while intramuscular glucagon was slightly more effective. The highest IRG concentrations were reached after intravenous administration, while intramuscular injection of glucagon was accompanied by the highest IRI release. These data indicate that intranasal administration of glucagon exerts metabolic effects similar to intramuscular and intravenous administrations. Further studies are needed to improve bioavailability and efficacy of intranasally administered glucagon.