Colonoscopy: Preparations For Patients Prescribed with 2L or 3L PEG (2PM to 5PM) Download PDF, 1.87MB, PDF Download PDF (Mandarin), 1 MB Polyethylene Glycol Electrolyte Solution (PEG) is used to clean out the gastrointestinal tract (stomach and intestines). Bisacodyl is a drug (laxative) which stimulates the muscle in the intestines, in order to create bowel movements (pass motion). Read on to find out how to prepare for a colonoscopy for patients prescribed with 2 litres or 3 litres of PEG for a procedure from 2pm to 5pm.You can also find out more about colonoscopy by scanning the QR code in the attached booklet, or click here. [Please download the PDF file if you are unable to view the image below.]