A child of this age could be having persistent gastro colic reflex which could make her pass stool after each feed and it could be entirely normal. For diagnosing a gastrointestinal infection I would have liked to look at the stool microscopy report. If pus cells are present in significant number, I would think of such an infection and would treat them with the antibiotics. I would suggest you to give oral rehydration solution (ORS) to replenish the salts and water lost. Enterogermina and sporlac are the right medicines to be prescribed and are safe to be given. You need not bother about side effects while giving these medicines. I and most other doctors prescribe these and no side effects are reported.