The TAE C14 has been evaluated as a diagnostic method of small bowel contamination in a group of patients operated for gastric disturbances. It has been compared with bacterial culture and bile salts chromatogrpahy of jejunum liquid and therapeutic response. 36 patients have been studied and divided in 3 groups: a) negative control: 8 subjects without pathology; b) positive control: 6 patients with intestinal resection and 1 with intestinal scleroderma, all of them with steatorrhea; c) gastric operated patients: 16 BII with and without vagotomy, 3 gastroenteroanastomosis and vagotomy, 1 superselective vagotomy and pyloroplasty and 1 B I, all the patients had steatorrhea, except one with BII. The period elapsed between the operation and the studies varied from 1 to 17 years (X: 4.9 +/- 4.1). The average value of steatorrhea was 23.9 +/- 10.2 g/24 hs. 100% of group b and 80% of group c had abnormal TAE C14. In 80% of the patients of the group c chromatogrpahy was performed and it agreed with TAE C14 in 80% of the studies. Bacteriology was positive in 100% of 18 studies, coinciding with TAE C14 in 70% patients. Therapeutic control of 100% of group c was positive in 90%.