A metabolic and functional assessment was carried out in 7 patients, who had undergone a restorative proctocolectomy with pelvic ileal pouch (Parks S-Pouch) between 8 and 38 months previously. The average follow-up was 22,5 months. The symptoms which led to the operation were in all patients ulcerative colitis. The mean faecal output per 24 h was 425.7 +/- 104 g, and the mean reservoir volume 233.5 +/- 102.3 ml. Within 24 h the average number of bowel movements has been 4.5 +/- 1.05 (range 3 to 6). One of the patients only uses a catheter for the evacuation. Two patients reported a degree of mucous leakage. The motility of the reservoir and of the anal canal showed the following pressures: In the pouch a medium pressure of 20.4 +/- 6.35 cm H2O was ascertained. The mean resting pressure in the anal canal was 88.88 +/- 20.9 cm H2O, mean voluntary contraction pressures were 211.8 +/- 42.2 cm H2O. The anal canal showed a length of 2.94 +/- 0.29 cm. In patients with mucous leakage the resting anal canal and maximal voluntary contraction pressures were no different to those who had mucous leakage and those who had not. A positive rectosphincteric reflex was observed in five patients. The absorption of vitamin B12 was reduced in two patients, one of them had a pathological D-Xylose Test. The other parameters like potassium, sodium, calcium, magnesium, iron, zinc phosphorus, TIBC, Transferin, Haemopexin, Folate and immunoglobulins were in all patients completely normal. The mean concentration of aerobic microorganisms was 7.18 +/- 1.33 log 10/g and for anaerobic 9.07 +/- 1.07; there was no evidence of a stagnant loop syndrome. Histological examination of the reservoir mucosa showed no evidence of superficial ulceration and crypt abscesses; an uncharacteristic inflammation of the ileum mucosa was proved in 6 patients. No cellular dysplasia, fibrosis, or progressive atrophy was seen in the present biopsies. In relation to the bladder and sexual function (one of the seven patients is a child) there were no problems.