Hypoglycemia is common in insulin, sulfonylurea, or glinide-treated diabetes where it is typically the result of the interplay of therapeutic insulin excess and compromised physiological and behavioral defenses against falling glucose levels. It is uncommon in the absence of diabetes where it is most commonly caused by drugs including alcohol among many others. Hypoglycemia is suggested by neurogenic (autonomic) and neuroglycopenic symptoms and signs of sympathoadrenal activation. It is confirmed by documentation of a low plasma glucose concentration with resolution of symptoms and signs after the glucose level is raised. In the short term, it is treated with oral carbohydrate, subcutaneous glucagon, or intravenous glucose. In the long term, it is prevented by correction of its original cause.