Based on theories of emotions and attributional processes (Schachter, 1964; Zillman, 1978, 1983), this study hypothesized that caffeine consumption would lead to an underestimation of the offender's aggression, less aggressive feelings toward the offender, and decreased willingness to shoot at the offender. To test these hypotheses, 52 police officers in Holland ingested 150 mg of either caffeine or vitamin C and then faced a videotaped Fire Arms Training System simulated scenario. In order to investigate police officers' shooting behavior, the researcher observed the police officers' behavior by scoring the videotapes. Three different types of behavior emerged: "not shooting," "shooting in time," and "shooting too late" (shooting at the offender after he had made his stabbing movement). The officer's impression of the offender was measured with a questionnaire, as was the officer's tendency to shoot. The findings support the hypotheses. The offender made a less aggressive impression on the officers who had consumed caffeine; caffeine consumption resulted in officers' decreased aggressive feelings toward the aggressive offender; and police officers were less likely to shoot at the offender as a result of caffeine consumption. 2 tables, 3 references, and 18 references