Colorectal cancer is the third most common cancer and the second most common cause of cancer-related deaths. Although newer, less invasive methods of colorectal cancer screening exist, such as guaiac and immunochemical-based fecal occult blood tests, colonoscopy examines the entire colon with high sensitivity and specificity, and allows for concurrent biopsy or polypectomy if necessary. Guidelines recommend colonoscopy every 10 years starting at age 50 and continuing until age 75; 90% of colorectal cancers occur in people aged ≥50 years. Colonoscopy may soon be recommended and used more frequently in patients with a family history of colorectal cancer, or in patients with inflammatory bowel disease. Pharmacists can counsel patients about the importance of colorectal cancer screening, what happens before or during the screening, and that proactive screening is necessary for drug shifts. Bowel preparation Bowel preparation requires dietary changes and laxatives (form). A low-fiber diet is recommended approximately 3 days prior to the colonoscopy, followed by a clear clear liquid diet 1 day prior to the examination, with no liquid food for at least 2 hours prior to the examination. When counseling patients about laxatives, pharmacists can recommend improving their taste, maintaining adequate hydration, and planning for adequate bowel movements. Medication management Most prescription and over-the-counter medications may be safe prior to colonoscopy; however, gastroenterologists may disagree regarding recommendations for discontinuing medications. Iron supplements should be discontinued 7 days prior to the colonoscopy. Iron can darken and stagnate stools, which can diminish clarity during the exam. Patients taking insulin and sulfonylureas are at increased risk for hypoglycemia and may require close monitoring or medication adjustments. The recommendation to continue antiplatelet agents or anticoagulants is based on the risk of screening (with or without polypectomy) and the risk of clinical indications (ischemic heart disease with or without coronary stenting). Role of the pharmacist The pharmacist can advise patients on bowel preparation diets and laxative therapies and emphasize the importance of adherence. In addition, the pharmacist can screen for high-risk medications or situations where medications must be temporarily changed or alternative laxatives selected.