Yes, it could. Hematochezia, or blood in your stool, could be caused by many things. Colon cancer, stomach ulcer, polyps, hemorrhoids, anal fissure are all possibilities. Once it is detected it should be investigated by a colonoscopy, especially if you are over 50. The exam is a lot easier than many people think, and I urge you to have a blood test and arrange for the scope. Your doctor can guide you.