To establish the diagnostic safety and the prognosis in outpatients with non-organic upper abdominal pain, 37 patients were followed up 5-7 years after the index investigation. In only one case had the diagnosis been changed during the follow-up period. This was in a man who erroneously had not been examined sufficiently before entry. He turned out to have gallstones. Eighty-one per cent still had abdominal pain, but 51% had improved (P less than 0.005). At the index investigation back pain was reported by 76% and headache by 60%. At the follow-up study back pain was unchanged in severity, but headache was significantly improved. The course of abdominal pain was significantly correlated with the course of back pain and headache. At the index investigation a psychic symptom score indicating vulnerability was significantly higher than in a matched patient group with well-defined pain. It was unchanged high at the follow-up study and unrelated to the course of the abdominal pain. Fifty-four per cent of the patients had symptoms of irritable bowel syndrome, but the course of the abdominal pain was unrelated to this.