• Screening for colorectal cancer
• Abdominal pain, changes in bowel movements, or weight lost
• Abnormal changes found on sigmoidoscopy
• Anemia due to low iron (usually when no other cause has been found) 
• Blood in the stool, or black, tarry stools
• Follow-up of a past finding, such as polyps or colon cancer
• Inflammatory bowel disease (ulcerative colitis and Crohn disease)