3 month old baby doing green potty with mucus 4 times day after .strickly breast feed but last week 1 time fed with formulae.

It depends!: The frequency, color and consistency of normal infant stools vary a lot. Green is not abnormal. Mucous can reflect inflammation, as in bacterial stool infection or an allergic problem. If your baby's stools became more frequent and contained mucous only after a bottle of formula, it may be a milk protein allergy. If the baby is feeding and acting well, i'd keep nursing and talk to the doctor.