Passage of blood through the rectum indicates an underlying disease of the anorectum or large intestine. It can be due to any of the following:

• Anal fissure
• Anorectal cancer
• Rectal ulcer
• Colon ulcer
• Colon cancer
• Ischemic colitis
• IBD
• Intestinal TB

Consult your doctor to identify the exact cause of blood in the stool.