The diagnosis of acute coronary occlusion has been facilitated and its treatment improved. At the onset of the attack the electrocardiogram may be normal or show only slight changes. The major therapeutic advances include oxygen administration, a low calorie diet, the judicious use of digitalis and quinidine, the avoidance of such drugs as Adrenalin and nitroglycerin, and the employment of anticoagulant and pressor drugs. Therapy must be individualized, particularly in reference to the time chair treatment is begun, the time of ambulation, and the time for returning to work. The majority of patients can be treated at home. The pain which ushers in the attack should be relieved immediately. For this purpose, morphine is most efficacious. Nitroglycerin is not effective, and may be dangerous. The patient's anxiety must be allayed; he should be reassured that he, like the vast majority of patients, will make a good recovery and resume a full, productive life. Indiscriminate prolonged bed-rest for all patients is inadvisable. The period of bed-rest is determined by the physical and psychic state of each patient. Some mild cases are permitted to be in a chair on the second or third day; others, after a week. Early chair treatment has definite advantages. In the average mild case, the patient begins to walk during the fourth week. The routine use of anticoagulants is unnecessary. They should be employed in patients with heart failure or shock, and in those who develop peripheral phlebitis, peripheral arterial embolism, or pulmonary embolism. When anticoagulants are administered, the patient should be under close supervision. We believe that anticoagulants, administered during the premonitory phase of coronary thrombosis, are inefficacious; they neither prevent nor hasten the progress of the thrombosis. Anticoagulants are contraindicated in patients with a history of bleeding tendency, ulcerative colitis, peptic ulcer, renal or hepatic disease, or a cerebrovascular accident. It is important to differentiate coronary occlusion from non-specific pericarditis, since anticoagulants appear to be harmful in this condition. The electrocardiogram should not be used as a criterion for determining the progress of the patient and the time when he may sit up, begin to walk, or return to work. Neither should undue reliance be placed upon the sedimentation rate as a guiding factor in treatment. The treatment of heart failure in coronary occlusion is the same as if coronary occlusion were not present, but special care is necessary to prevent digitalis intoxication. A low calorie diet is important, for it diminishes the work of the heart, prevents gastrocardiac reflexes, and reduces weight in the obese. Constipation and distention must be prevented. Cold milk and fruit juices should be avoided and laxatives used. Nausea and vomiting are benefited by the oral or intramuscular administration of anti-motion sickness drugs. Early treatment of shock is essential. The vasopressor drugs are helpful, if administered early. If congestive failure is a factor, strophanthin or digitalis should be given. Pulmonary edema requires immediate treatment with morphine. If necessary, aminophylline, strophanthin, mercurials, oxygen under pressure, and rotating tourniquets or phlebotomy are employed. The inhalation of alcohol vapor is occasionally efficacious. Arrhythmias occur frequently and often remit. The indications for the treatment of each type are discussed and the details outlined. Quinidine is not used routinely. Hiccough may be a serious problem. Reassurance of the patient is most important. Adequate sedation should be used. Numerous successful therapeutic measures are available. Cortisone and ACTH are not efficacious in coronary occlusion. Antibiotics are administered if pulmonary congestion or signs of congestive heart failure are present, or if the temperature is above 102° F. Whiskey should not be given in acute coronary occlusion, since it may increase the pulse rate. Smoking should be prohibited. The prognosis in coronary occlusion has greatly improved during the past 30 years. In private practice, the mortality rate during the first attack is now five per cent or less. Most patients can be rehabilitated within two or three months. The vast majority makes a fair or good recovery, more than half make an excellent functional recovery. Four out of five return to work.