Bleeding per rectum or Blood in stools is an important warning symptom of Cancer of Colon or Rectum. Left sided colon cancer present with Recent change in bowel habit with alternating diarrhoea or constipation associated with blood in stools. Right sided colon cancer usually present with constipation or with Undiagnosed anaemia. Blood in stools can also be because of other noncancerous conditions. Important is to notice this symptom and report to physician for knowing and treating the cause of Blood in stool. So dont neglect this symptom and consult your family physician at the earliest. Consult Dr Jaipalreddy to know more on colon cancer symptoms , treatment options and overall survival.