PEG solution (Laxabon®) 4L is used for large bowel cleansing in many centers in Sweden and is the standard regimen used in our colonoscopy unit. In this study we compare this standard regimen with senna glycoside (Pursennid® Ex-Lax) 36mg (tablets) taken orally in the night before the colonoscopy and 2L Laxabon® solution orally starting to drink the solution four hours prior to the colonoscopy.