A method of treating congenital hyperinsulinism in a subject is disclosed. The method can include parenterally administering to the subject a first composition comprising a glucagon, a glucagon analogue, or a salt form of either thereof, and optionally administering to the subject a second composition comprising glucose, a glucose analogue, or a salt form of either thereof, wherein administration of the first composition sufficiently increases blood glucose level in the subject such that the second composition is not administered or the second composition is administered at a glucose infusion rate (GIR) of less than 8 mg/(kg*min).
