Abstract A study comparing the symptoms and signs of patients with acute Crohn's disease and those with acute appendicitis and intestinal obstruction is reported and a preliminary evaluation of computer-assisted diagnosis in this problem is given. There are significant differences between the three conditions. However, the accuracy of computer-assisted diagnosis in Crohn's disease is reduced by the high false positive rate of diagnosis in both appendicitis and intestinal obstruction. Computer accuracy in Crohn's disease may increase when further information is available to extend the data base.