The research considered all trauma victims admitted from the scene of injury to the trauma center. The victims included 67.3 percent who were injured as a result of vehicular trauma and 32.4 percent injured from other kinds of trauma. Most were men (72.8 percent) who were 30 years old or younger (58.4 percent). Radioimmunoassay for marijuana resulted in detection of activity of 2 nanograms per milliliter or more in 34.7 percent of the participants. Positive blood alcohol levels were found in 33.5 percent of the participants. Vehicular and nonvehicular trauma victims did not differ significantly in marijuana use, but marijuana use was higher among those 30 years old or younger and among men. However, positive blood alcohol was more frequent among traffic crash victims than among victims of other kinds of trauma. The use of marijuana and alcohol in combination (16.5 percent) was highly significant compared with marijuana aloe (18.3 percent), alcohol alone (16.1 percent), or neither drug (49.1 percent). Injury severity did not correlate with either drug. Tables and 30 references