If your 8-month-old baby is having difficulty with bowel movements and only going every 4-5 days, it would be a good idea to consult with a pediatrician to determine the cause. In the meantime, you can try gradually introducing fruits, vegetables, and less constipating cereals into their diet. Adding linseed oil for lubrication and ensuring proper hydration can also help. Prune puree and juice may also aid in regular bowel movements. It's important to seek medical advice if the issue persists. A pediatrician may prescribe a laxative to help regulate their bowel movements.