Legal doctrine in common law jurisdictions reflects a concern that some types of evidence may lead to bias in jury decision making, and that prejudice can be driven by the emotional reactions of jurors to the evidence. The current study extends previous research by examining the synergistic influence of gruesome details and injury severity In a mock jury study, 240 first-year psychology students were assigned to one of two visual evidence conditions: neutral and gruesome photographs, and one of two injury severity conditions: moderate injury severity and high injury severity. Participants were further assigned to one of two information processing conditions in which they were instructed to process information in either the rational or experiential mode. The main findings were: (1) mock jurors who read about a more severely injured plaintiff were more sympathetic towards the plaintiff compared with mock jurors who read about a less severely injured plaintiff; (2) mock jurors exposed to gruesome photographs rated the defendant as significantly more negligent compared with mock jurors exposed to neutral photographs. Implications of these findings are that gruesome photographic evidence may bias jurors' perceptions of the responsibility of the plaintiff and defendant.