Thanks for the query. Food allergies may cause mucous in baby’s stool. Foremilk / hindmilk imbalance - Baby is drinking too much of the high lactose foremilk while breastfeeding. Teething causes mucous in stool because your baby has an excess of saliva while teething, which can cause mucous in stool. A virus may cause frequent watery stools, due to diarrhea and they may come with mucous in them. A green mucous stool is sometimes due to a virus. Malabsorption, which is when Baby is not absorbing nutrients from breast milk or formula, also causes mucous in the stool. This is a very rare occurrence. These are some causes of mucus in stool with abdominal pain. Continue antibiotics as you have already started it, give anti- flatulent or antispasmodic drops for abdominal pain. Try some probiotics like sporlac. Hope it will help.