The aim of the study is to determine if more force is used during colonoscopy when patients receive monitored anesthesia with propofol versus conscious sedation. Force measurements will be performed using the colonoscopy force monitor (CFM). This device measures the magnitude and direction of force applied to the insertion tube of a standard colonoscope during colonoscopy.

Randomized factorial design of colonoscopy with either propofol administered anesthesia or conscious sedation. Twelve experienced endoscopists from community and academic centers will perform colonoscopy using either propofol or conscious sedation on a group of 12 patients for each endoscopist for a study total of 144 patients. An equal number of male and female patients will be included in each group.

Inclusion Criteria:

• Male or female
• Age: 30-75 years
• ASA Class I or II
• All ethnic and racial groups will be included

Exclusion Criteria:

• Colonic pathology that in the opinion of the endoscopist could interfere with the colonoscopy. Examples include: colonic stricture, poor preparation, obstructing tumor.
• Specific pathology that would limit the extent of examination
• ASA class 3 or greater
• Pregnancy
• Monitored anesthesia using propofol for sedation.
• Vulnerable subjects. Students, nursing home residents, institutionalized patients, and those with psychological or physical incapacity

All adult male and female patients between the ages of 30 and 75 presenting to the participating sites for screening or diagnostic colonoscopy to be performed by any of the investigators will be considered for inclusion.