The purpose of the study is to evaluate the efficacy and safety of bisacodyl combined with escalating doses of lactulose to be used as a preparation for colonoscopy.

Inclusion Criteria:

• Patients requiring bowel evacuation for colonoscopy.

Exclusion Criteria:

• Patients with galactosemia (galactose-sensitive diet).
• Patients known to be hypersensitive to any of the components of lactulose for oral solution.
• Patients with a known abnormality on screening or a vital sign assessments that, in the Investigator's judgment, may pose a significant risk including those pertaining to dehydration or electrolyte shifts.
• Patients with a history of impaired renal function.
• Patients with current or recent history of hypotension, as defined by the Investigator.
• Patients with a history of long Q-T syndrome.
• Patients with a history of a failed bowel preparation.
• Patients with severe constipation, defined as those patients taking daily prescription or over-the-counter laxatives.
• Patients with possible bowel obstruction, gastric retention, bowel perforation, toxic colitis, toxic megacolon, ileus or previous colonic surgery (except hemorrhoidectomy and polypectomy).
• Patients on lactulose therapy or receiving any treatment for chronic constipation.
• Be pregnant or nursing.
• Patients expected to require electrocautery or argon plasma coagulation.
• Patients less than 18 years of age.
• Inability to understand the requirements of the study or be unwilling to provide written informed consent (as evidenced by signature on an informed consent document approved by an Institutional Review Board [IRB]) and agree to abide by the study restrictions.
• Be otherwise unsuitable for the study, in the opinion of the Investigator.

All patients adhered to the one set of study-level eligibility criteria.

Adverse Events were collected from the first dose of study drug through the end of the observation period after the colonoscopy (Day 2).