My baby have not poop since for 4 days. She is currently 4 months old and is exclusively breastfed. Is it something to be worried about? I'm really worried.

Babies often go a long time between bowel movements. Most of the time, it is normal for a baby to go days or even more than a week without a bowel movement. However, a baby may sometimes be constipated and need a little help. Exercise and warm bath should help relieve the discomfort. If it still persists, since you are breastfeeding your baby, you could eliminate certain foods, such as dairy, from your diet. It may take some trial and error to identify the dietary changes that help.