An enema containing the osmotic agent polyethylene glycol (PEG) 3350, also called macrogol 3350, with laxative activity. Upon rectal administration of the PEG3350-containing enema NER1008, PEG creates an osmotic gradient, which promotes the retention of water in the bowel. This increases the water content of stool, which results in increased gastrointestinal (GI) motility, decreased stool transit time and evacuation of colonic contents.