Acute intoxication with either cocaine or methamphetamine may contribute to formation and rapture of a berry aneurysm by causing transient hypertension and tachycardia. We report the results of a retrospective study to determine the incidence of acute cocaine or methamphetamine intoxication in deaths due to ruptured berry aneurysm in our jurisdictions. We reviewed all deaths from ruptured cerebral aneurysms that fell within our jurisdictions during the seven years from 1 January 1987 to 31 December 1993 and found 83 cases. The mechanism of death invariably involved subarachnoid hemorrhage, although some cases also had intracerebral hemorrhage. A history of drug abuse was found in 13 cases. Toxicological analysis was performed in 39 cases. Of these methamphetamine was detected in six cases and cocaine in three cases-an incidence of 21%. (In one case both methamphetamine and cocaine were detected.) The incidence of acute cocaine intoxication in all autopsies in Jefferson County was 13.6%. The incidence of methamphetamine intoxication in all autopsies in San Diego County was 4.9%. Although the exact mechanism by which berry aneurysms form remains undetermined, research indicates that propagation and rupture of the aneurysm are aggravated by hypertension and tachycardia, both of which are pharmacologic side effects of cocaine and methamphetamine. Based on the preponderance of methamphetamine associated with deaths due to ruptured berry aneurysms it appears that methamphetamine is more toxic than cocaine, perhaps owing to the longer half- life of methamphetamine.