The present study is intended to evaluate the effectiveness, tolerability, compliance, and feasibility of the low volume bowel preparation, bisacodyl tablets followed by 2L Polyethylene glycol (PEG) with citrate and simethicone (CS) given the same day of colonoscopy, vs the standard 4L split PEG solution.

Eligible patients will be informed about the aims, procedures, benefits and possible risks of the study prior to sign the informed consent form from day -30 to day-3. They will provide medical history and undergo a physical examination. Patients will be evaluated by a Physician other than the blind Endoscopist. The same responsible person will instruct the patients about administration procedures in both oral and written form. The patients will be assigned to receive one of the dosing schedule bowel preparation according to a computer generated block-randomisation list. Patients will take the study treatment at home according to the given instructions. Patients will return to the clinic for colonoscopy. The colonoscopy will be performed by an Endoscopist who will be unaware of the bowel dose-regimen preparation taken by the patient. Completed colonoscopic exam will be performed with time recorded (intubation and withdrawal from ceacum). The unblind Investigator will ask the patients about safety, tolerability, overall acceptance and compliance.

Inclusion Criteria:

• Out-patients undergoing a complete colonoscopy
• Patient written informed consent

Exclusion Criteria:

• Pregnant or lactating women or at a risk of becoming pregnant
• Known or suspected gastrointestinal obstruction or perforation; toxic megacolon; major colonic resection Known or suspected hypersensitivity to the active principle and/or formulations' ingredients