A study has been made of diagnostic errors and delays in 140 patients with Crohn's disease. Results were correlated with the site of the disease. Only 13% of patients with small-bowel disease and 21% of the group as a whole were correctly diagnosed after initial investigation. A large number of misdiagnoses were made, and these were often multiple. Of patients with small-bowel disease, 19% were first thought to be suffering from a psychiatric disorder.