Loperamide vs. Placebo's Effect on Ileostomy Output: A Clinical Randomized Blinded Cross-over Study

The aim of this study is to quantify the effect of Loperamide on ileostomy output in patients operated for rectal cancer, ulcerative colitis and in patients with short bowl syndrome. These patients are recruited through The Department of Surgery and The Department of Gastroenterology, University Hospital Odense. The effect of Loperamide will be evaluated against Placebo in relation to the following parameters: * Change in ileostomy output in g/day in relation to oral intake * Quantification of the change in intestinal transit time using a radiopaque marker * The patient´s own assessment on which period they received Loperamide or Placebo Construction of a stoma is a frequently used part of the surgical treatment of intestinal cancer and chronic intestinal inflammation. More than 60% of patients with an ileostomy develop dehydration and loss of salts and minerals, due to an excessive stoma output. The most common method used to reduce stoma output is Imodium® ( Loperamide ). The effect has never been studied extensively, probably because it is an over the counter medicine. The treatment is relatively expensive and also subject to side effects, even if they are mild. Therefore, the investigators found it relevant to perform a clinical study to determine the effect. The results will be important for future patient treatment. The study is a clinical blinded randomized crossover study. The study includes three types of patients. Patients operated for rectal cancer or ulcerative colitis with a temporary or permanent ileostomy, and patients with short bowel syndrome with a permanent ileostomy. The first two types of patients will be recruited through two ways. * During hospitalization in connection to their operation at The Department of Surgery, University Hospital Odense. The patients are offered inclusion into the study either before or after surgery depending upon the clinical situation. For those who consent and fulfills the inclusion criteria, the study starts up on 7th day after surgery. * Through their regular controls in the stoma clinic. Patients with short bowel syndrome are offered inclusion through their contact with The Department of Gastroenterology, University Hospital Odense, if they meet the criteria for inclusion. Patients will undergo to periods during the study. They will be randomized to start with either Loperamide or Placebo. Each period consists of 3 days. Day 1 - Uploading of the drug Day 2 - Collecting of stoma output when necessary Day 3 - Radiopaque marker and collection of stoma output every two hours After 7 days without medicine intake the patient starts the second period with the opposite drug. During day 2-3 the patient will register and weigh all food and fluid intake.