The aim of this study is to compare a new regimen of reduced bowel preparation that does not include low fiber diet with another reduced bowel preparation including low-fiber diet.

Bowel preparation should be safe and well tolerated by patients, particularly in a screening setting. For this reason, limited bowel preparations have been extensively investigated. Usually, they combine the use of low-fibre diet and faecal/fluid tagging. The ingestion of a positive contrast agent (either barium, iodine or a combination of the two),needed to differentiate stool or fluid residues from true colonic lesions, is now considered mandatory. A low-fibre diet has the aim of improving residue homogeneity and facilitates tagging; however, there aren't significative evidences at support. The aim of this study is to compare a new regimen of reduced bowel preparation that does not include low fiber diet with another reduced bowel preparation including low-fiber diet. Primary outcome is the overall quality of bowel preparation.

Inclusion Criteria:

• Asymptomatic patients (Screening Patients)
• Symptomatic patients unwilling to undergo optical colonoscopy (Symptomatic Patients)
• Patients with a previous incomplete optical colonoscopy.

Exclusion Criteria:

• Allergy to Macrogol
• Cognitive behavioral deficits