This is the most common cause of rectal bleeding, usually the type that stains toilet paper. It happens when veins in your anus and rectum swell. Among the causes: obesity, pregnancy, and straining during bowel movements. It’s not an emergency. Along with bleeding, hemorrhoids cause itching, pain, and irritation. If you add fiber to your diet, drink more water, avoid sitting for long periods, and get more exercise, your condition may improve. Over-the-counter creams or soaking in a sitz bath could bring relief, too.