The object of this study was to determine if the presence of sympathomimetics (cocaine, benzoylecgonine, or amphetamine), detected by routine urine toxicology screen, affect the initial presenting pulse, blood pressure, respiratory rate, or level of consciousness in trauma patients. A retrospective chart review was performed on 1,679 patients enrolled in an urban level 1 trauma registry between October 1987, and July 1992, for whom complete toxicology data were available. There were no clinically significant differences in the vital signs of patients with positive toxicology screens and those with negative screens. There was a statistically significant increase in prehospital respiratory rate among patients with benzoylecgonine or amphetamines on admission toxicology screens when potential confounding factors were controlled. However, these effects disappeared upon arrival at the hospital. The detection of sympathomimetics by toxicology screening had no effect on pulse and systolic blood pressure when age, sex, mechanism, type, and severity of injury, prehospital IV fluid volume, and alcohol intoxication were controlled.