What are the causes of anal bleeding?

Common causes of anal bleeding include: 1. Hemorrhoids: Prolonged sitting, constipation, and other factors may lead to hemorrhoids. When the hemorrhoids increase in size, the mucosal surface can be easily irritated and bleed during bowel movements, typically presenting as bright red blood dripping with stool. 2. Anal fissure: Hard stools and straining during bowel movements may cause tears in the anal skin, resulting in an anal fissure, which can lead to anal bleeding and pain. 3. Rectal lesions: Conditions such as rectal polyps or rectal tumors may cause bleeding when the lesion's surface vessels rupture due to prolonged irritation from bowel movements, especially when the lesion is large. 4. Enteritis: Inflammatory diseases such as proctitis or colitis may cause congestion and swelling of the intestinal mucosa, leading to blood in the stool.