Nineteen patients with congestive heart failure were given a continuous infusion of glucagon 3 to 5 mg/hour. Those with acute processes improved, while only 1 of 12 with chronic CHF benefited. Urine output increased 495 ml/24 hours, BUN rose 4.9 mg percent, serum glucose increased 22.1 mg percent, and serum potassium decreased 0.35 mEq/liter. No induced arrhythmias were noted, even in the presence of digitalis toxicity. Evidence of increased “ischemia” (angina, depressed ST segments and inverted T waves) during the infusion were seen in four patients. In chronic congestive failure associated with coexisting manifest chronic obstructive pulmonary disease or pulmonary heart disease, the response to glucagon was uniformly unfavorable. Glucagon should be reserved for acute CHF and then only after other modes of therapy, especially digitalization, are unsuccessful. Nineteen patients with congestive heart failure were given a continuous infusion of glucagon 3 to 5 mg/hour. Those with acute processes improved, while only 1 of 12 with chronic CHF benefited. Urine output increased 495 ml/24 hours, BUN rose 4.9 mg percent, serum glucose increased 22.1 mg percent, and serum potassium decreased 0.35 mEq/liter. No induced arrhythmias were noted, even in the presence of digitalis toxicity. Evidence of increased “ischemia” (angina, depressed ST segments and inverted T waves) during the infusion were seen in four patients. In chronic congestive failure associated with coexisting manifest chronic obstructive pulmonary disease or pulmonary heart disease, the response to glucagon was uniformly unfavorable. Glucagon should be reserved for acute CHF and then only after other modes of therapy, especially digitalization, are unsuccessful.