More than a third of 1,023 patients treated at a hospital for serious accidents used marijuana before being injured, according to a study.

Another third of the patients at the University of Maryland's Shock Trauma Center drank alcohol before being hurt, and 16.5 percent had used both marijuana and alcohol, the study said."To me, it was rather startling to see that an illicit drug matched in use by a legal drug," said Dr. Carl A. Soderstrom, a surgeon who headed the research project at the Maryland Institute for Emergency Medical Systems.

Patients were unaware of the study, which used blood samples. The research was reported in the June issue of the journal Archives of Surgery.

"If this is borne out in other studies across the country, it puts a new slant on the safety of marijuana use," Dr. Edward J. Cone of the Johns Hopkins Addiction Research Center said Wednesday.

The study showed that 34.7 percent of the 1,023 patients had used marijuana and 33.5 percent were under the influence of alcohol. Ninety-two percent of the patients survived.