Colonoscopy is a routinely performed examination of children and adolescents in the diagnostic process of inflammatory bowel disease (IBD). It is necessary that the bowel is clean so the colonoscopy can be optimally performed. The cleansing of the bowel by means of laxatives prior to the examination is, however, considered difficult by many children. Getting smaller children to cooperate and to drink a substantial volume of laxative fluid prior to the examination can be particularly difficult. There are several possible cleansing procedures and combinations of procedures for the cleansing of the colon, for example by means of polyethylene glycol and sodium picosulphate, which are the two most commonly used methods. Cleansing by means of polyethylene glycol can, due to the necessary intake of a substantial quantity of fluid, be particularly frustrating for patients. Often the only way to carry out the preparation is with the insertion of a nasogastric tube, which can cause discomfort for some children. Cleansing the colon by means of sodium picosulphate, which involves an intake of a small quantity of fluid, has been suggested to be a good sufficient method resulting with a satisfactory result in terms of bowel cleanliness. However, studies have so far encompassed only a smaller number of children and further studies are needed to confirm that there is no difference between the two methods in terms of resultant bowel cleanliness.