Hemorrhoids: This is the most common cause of rectal bleeding, especially if the blood is mixed with stool. Hemorrhoids are swollen veins in the rectum or anus that can bleed, especially during bowel movements.

Diverticulosis: A condition where small, bulging pouches (diverticula) develop in the digestive tract, most commonly in the colon. These pouches can bleed, leading to rectal bleeding mixed with stool.
Anal Fissures: Small tears in the lining of the anus can cause bleeding, especially during bowel movements.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause inflammation and bleeding in the digestive tract, leading to rectal bleeding mixed with stool.
Gastrointestinal Infections: Infections like gastroenteritis can cause inflammation and bleeding in the digestive tract.

Colorectal Cancer: Although less common, colorectal cancer can cause rectal bleeding mixed with stool. It is crucial to rule out this diagnosis, especially in older adults or those with a family history of colorectal cancer.
Angiodysplasia: A condition characterized by abnormal blood vessels in the colon, which can cause bleeding.
Ischemic Colitis: Reduced blood flow to the colon can cause inflammation and bleeding.

Intussusception: A condition where a part of the intestine slides into another part, causing bleeding and obstruction.
Meckel's Diverticulum: A rare congenital condition where a small pouch in the small intestine can cause bleeding.
Vascular Malformations: Abnormal blood vessels in the digestive tract can cause bleeding.
Infectious Colitis: Certain infections, like those caused by E. coli or Salmonella, can cause colitis and rectal bleeding.