If your baby hasn't had a bowel movement in 5 days, you can try increasing their fluids intake and giving them foods rich in fiber like prunes, oatmeal, barley, and sweet potatoes. You can also try massaging their belly in a clockwise direction and encourage them to do bicycle-like movements with their legs. If these methods don't work within 1 or 2 days, you can consider using a laxative after consulting with a doctor. It's important to address constipation in babies promptly to avoid any underlying health issues.