1.   Methods Twenty three patients who had undergone restorative proctocolectomy with ileal reservoir were included in the study.

2.   The mucosa of the pelvic ileal reservoir undergoes adaptive changes -- inflammatory, architectural and metaplastic -- on exposure to the faecal stream.

3.   The formation of a pelvic ileal reservoir results in pathological changes in the ileal mucosa in most patients regardless of the initial diagnosis.

4.   Pelvic ileal reservoirs have been shown to express colonic phenotypic changes and it has been suggested that the reservoir mucosa undergoes complete colonic metaplasia.

5.   Twenty three patients who had undergone restorative proctocolectomy with ileal reservoir were included in the study.

6.   Various microbiological changes have been observed in pelvic ileal reservoirs, although these have not been consistent.

7.   This study has shown that colonic phenotypic changes are very common in ileal reservoirs when several biopsy specimens are analysed.

8.   A consistent feature of pelvic ileal reservoirs is the difference in inflammatory scores, particularly of active inflammation, between patients with ulcerative colitis and those with FAP.

9.   Twelve patients had quadruplicated ileal reservoirs, four had duplicated reservoirs, and two patients underwent straight ileoanal anastomoses.