Illness scripts are knowledge structures composed of consequences, enabling conditions, and faults. The effects of illness script components--consequences and enabling conditions--and physician factors on referral decisions for gastrointestinal disorders were investigated. The hypothesis that consequences and enabling conditions increase the likelihood of referral was confirmed and several interactions between consequences and enabling conditions were found. The hypothesis that physician factors moderate the effect of enabling conditions was also confirmed, but (contrary to illness script theory) evidence was also found for moderation of consequences. Both enabling conditions and consequences were found to be moderated by physician factors to a larger extent than previously assumed by illness script theory.