Carotid artery ligation, whether elective or an emergency, is an operation that most head and neck surgeons do with some trepidation because of the possible neurologic consequences. Of 440 major head and neck operations for cancer in which the carotid artery was exposed, 20 (4.5%) patients suffered a carotid rupture or had the vessel ligated just prior to rupture. We describe the typical patient and his management. Of these 20 patients, five died as a direct result of rupture or ligation, ten survived rupture and/or ligation with neurologic sequelae, and five survived rupture and/or ligation without neurologica sequelae. Of the ten patients with neurologic problems, four had immediate strokes, and six had delayed strokes, ie, these occurred greater than eight hours after ligation. Seven patients who required carotid artery ligation, separate from the previously mentioned group, received 5,000 units of heparin sodium subcutaneously every 12 hours in a prospective study. Of these seven patients, one died immediately postoperatively, and six survived without any neurologic sequelae. We discuss the cause of delayed neurologic problems and the rationale for the use of low-dose heparin.