We report the specifics of 12 cases of severe hypertension after the intraoperative use of topical phenylephrine, submucosal epinephrine, or both. Ten of these 12 patients also developed severe pulmonary edema. Seven of the twelve were treated with β blockers; 3 of whom suffered cardiac arrest. We propose a common mechanism: the vasoconstrictors caused systemic hypertension, increased left ventricular afterload, decreased left ventricular compliance, and decreased cardiac output. In those patients treated with β blockers, decreased contractility and inability to increase heart rate further compromised cardiopulmonary function. (Otolaryngol Head Neck Surg 1997;117:56–61.)