Hi, I am Dr.Shreyash Mehta, MD Community Medicine. Signs and symptoms of colon cancer include: A change in your bowel habits, including diarrhea or constipation or a change in the consistency of your stool Rectal bleeding or blood in your stool Persistent abdominal discomfort, such as cramps, gas or pain A feeling that your bowel doesn t empty completely Weakness or fatigue Unexplained weight loss Presence of occult blood in stools may be due to upper gastrointestinal bleeding or lower gastrointestinal bleeding Diverticular disease Anal fissure Colitis- inflammation of the colon Angiodysplasia-A condition in which fragile, abnormal blood vessels lead to bleeding. Peptic ulcers Polyps Cancers- like oesophageal cancer/ gastric cancer/ colorectal cancer Oesophageal varices Adenoma Sickel cell anaemia I advise you to visit the physician if you have aforementioned signs and symptoms. If you are still suspicious about yourself having occult blood in stool then you can buy certain kits available in market for detecting occult blood in stools. They are better option then pouring peroxide over the stool. If you do get the test positive then the next step in the workup is a form of visualization of the gastrointestinal tract by one of several means Sigmoidoscopy Colonoscopy Virtual colonoscopy Endoscopy Then one can diagnose colon cancer. But I advise you to relax stop thinking too much, you can visit your family physician.