Using MMPI test, 196 patients with duodenal ulcer were studied for their personal traits. The patients' personality was characterized by a high level of anxiety, mental tension, emotional immaturity, affective rigidity, suppressed aggression. The most apparent in the young adults were deviations from the norm of psychopathic nature; as patients grew older, their illness of longer duration, their personal profile tended to be dominated by a problem of suppressed aggression and emotional immaturity, with hypochondriac and depressive tendencies to be on the increase. The personal traits did not appear to be dependent upon severity of the disease course or much affected by the treatments administered that incorporated tranquilizers, antidepressants and a novel synthetic opioid hexapeptide dalargin.