Certain drug interactions have become of increasing interest to anesthesiologists as a result of complications which may be induced during general anesthesia. In recent years, the beta adrenergic blocking drug, propranolol, has been employed in the treatment of severe cardiac arrhythmias and for angina pectoris in an effort to decrease the work of the myocardium. Because of its myocardial depressant effect, added to that produced by most anesthetic drugs, our contributors are of the opinion that, if possible, propranolol therapy should be discontinued at least 24 hours and possibly longer prior to subjecting a patient to general anesthesia.