[header] How to recognize colon cancer symptoms [title] Pay attention to blood in your stool. [step] If you have ongoing rectal bleeding that doesn't seem to be a result of hemorrhoids or a tear, it's a good idea to go to the doctor and get checked out. Blood in the stool is a common symptom of colon cancer. 
[substeps] Blood can make your stool look either bright red or black. If you are not sure whether you see blood or not, be safe and contact your doctor nonetheless.