Blood in stool, or pooping blood, can be caused by various conditions ranging from minor to serious. Common causes include hemorrhoids (swollen veins in the rectum or anus), anal fissures (small tears in the anus), constipation and straining to pass hard stools, inflammatory bowel diseases such as Crohn's disease or ulcerative colitis, infections, and in some cases, colon polyps or cancer. The color of the blood can provide clues about the source: bright red blood usually indicates bleeding in the lower digestive tract (rectum or anus), while darker blood may indicate bleeding higher up in the digestive tract. If experiencing blood in stool, especially with other symptoms like pain, weight loss, or persistent bleeding, it is important to seek medical evaluation for an accurate diagnosis and appropriate treatment.