Hemorrhoids: This is the most common cause of fresh blood discharge after defecation. Hemorrhoids are swollen veins in the lowest part of the rectum or anus, and they can bleed, especially during bowel movements.

Anal Fissure: A small tear in the lining of the anus can cause pain and bleeding during and after bowel movements.
Diverticulitis: Inflammation of the diverticula (small pouches) in the wall of the colon can lead to bleeding.
Colon Polyps: Growths on the inner lining of the colon can cause bleeding, especially if they are large or have become cancerous.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic inflammation and bleeding in the colon.

Colorectal Cancer: Although less common, colorectal cancer is a critical diagnosis that must not be missed. It can present with rectal bleeding, especially in older adults.
Infectious Colitis: Certain infections, such as those caused by bacteria, viruses, or parasites, can lead to inflammation of the colon and rectal bleeding.
Ischemic Colitis: Reduced blood flow to the colon can cause tissue damage and bleeding, which is more common in older adults or those with cardiovascular disease.

Angiodysplasia: A condition characterized by the presence of abnormal blood vessels in the colon, which can cause bleeding.
Solitary Rectal Ulcer Syndrome: A condition where an ulcer forms in the rectum, often due to chronic straining during bowel movements, which can cause bleeding.
Intussusception: A rare condition where a part of the intestine slides into an adjacent part, which can cause bowel obstruction and bleeding.
Vascular Malformations: Abnormal formations of blood vessels in the colon or rectum can cause bleeding, though this is rare.