Abstract
Since birth the boy frequently developed vomiting and diarrhea, eventualy his weight gain was only 400g in the first year of life. Then he frequently had abdominal pain and severe diarrhea which needed repeated hospitarization. In his 12th year the GI series revealed Crohn's disease, and in his 16th year when his body weight was only 18.5kg, height 130cm, ileostomy associated with intraabdominal abscess and secondary cystitis developed. He was treated with no-oral-intake and intravenous hyperalimentation. Two months later resection of the damaged part of ileum was done. During three months after the operation he gained 5kg in weight and 2cm in height without symptom. Purberty, however, was not yet observed.