Antibiotics can cause problems, most babies with milk allergy are allergic to cow’s milk protein, bloody stool after antibiotics would try and sit tight and see what the results say. While others are allergic to soy protein, and some to both. Fed infants normally have stools that look like watery; yellow cottage cheese.
Many times I don’t pass any stool, me concern is the mucus I am seeing in her stool. First had more mucus, there is a bunches of mucus the size of a quarter in her stool.