This thesis describes new concepts pertaining to the continent ileostomy. The aim of the study was twofold: to counter valve desinvagination and to simplify pouch construction. In Chapter 1 a survey is given of the history, the present situation of the technique and the complications of the continent ileostomy. It appears that on the one hand the operation improves the quality of the patient's life, but on the other hand the operation gives rise to many complications. The number of complications quoted in the literature varies and has been reported to be as high as 43%. Most of the time this led to repeat surgery, with equally uncertain results. This is the reason why the operation is not very frequently performed. Most of the time the complications concern the valve system and to a lesser degree the reservoir. In order to obtain a better insight into the origin of and possible gain better control over these complications an investigation was carried out on laboratory animals. This investigation involved: the complications of the valve system, the effect of the suturing method on the function of the reservoir and the simplification of the construction of the reservoir. In Chapter 2 the aim of the investigation was formulated in three questions. 1. Is it possible to diminish the chance of complications of the valve system of the continent ileostomy? 2. Does the method of suturing influence the function of the reservoir? 3. Is it possible to simplify the construction of the reservoir, so that the duration of the operation can be shortened? Chapter 3 is the general materials and methods section. Chapter 4 is about the research on the valve system. Up to now, no method of suturing the valve has consistently produced results good enough to make subsequent re-operations unnecessary. In this study two types of valve experiments have been carried out. First the feasibility of circumventing the problems of the nonpermanent form of the valve was investigated combining a short papilla with a 10 centimeter long, anti-peristaltic sutured section of the ileum. The assumption was that permanence of the form would be more easily obtained in a shorter valve (2 centimeter instead of 5 centimeter). After an initial period of continence, incontinence occurred on the average after 10 months. Autopsy showed that the short papilla had disinvaginated.(ABSTRACT TRUNCATED AT 400 WORDS)