A colonoscopy is a standard medical procedure used to diagnose and treat gastrointestinal tract conditions, particularly those affecting the large intestine (rectum, colon, and anus) and a portion of the small intestine (the ileum). It is the most effective and widely accepted screening tool for colorectal cancer and other digestive disorders.

Colonoscopies are recommended for adults starting at age 45, or earlier for those with a family history of colorectal cancer or certain symptoms. The preparation involves a clear liquid diet and a bowel-cleansing solution to ensure the colon is clean for optimal visualization. Most patients can resume normal activities within 24 hours after the procedure.

A colonoscopy can help diagnose various conditions including colorectal cancer, Crohn's disease, ulcerative colitis, diverticulosis, and gastrointestinal bleeding. The procedure has a high accuracy rate for detecting abnormalities in the colon and is considered the gold standard for colorectal cancer screening. It is generally safe with minimal risks when performed by an experienced gastroenterologist.