Acute intoxication with either cocaine or methamphetamine may contribute to formation and rupture of a berry aneurysm by causing transient hypertension and tachycardia. This study reviewed all deaths from ruptured cerebral aneurysms that fell within the researchers' jurisdictions during the 7 years from January 1, 1987, to December 1993 and found 83 cases. The mechanism of death invariably involved subarachnoid hemorrhage. A history of drug abuse was found in 13 cases. Toxicological analysis was performed in 39 cases. Methamphetamine was detected in six of these cases and cocaine in three cases--an incidence of 21 percent; in one case, both methamphetamine and cocaine were detected. The incidence of acute cocaine intoxication in all autopsies in Jefferson County was 13.6 percent. The incidence of methamphetamine intoxication in all autopsies in San Diego County was 4.9 percent. 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 pharmacological 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. 1 table and 16 references