What Causes Frequent Stool With Greenish Color In Breast Fed Infant?

Hi My son is 5 month old and depend on mother milk , from past 10 he started having motion more then 10 times , Which was not the case earlier and was having once or twice max, the Stoll colour is green with mucus , we consulted ti doctro and they gave Antibiotic which did not improved situation any more Now we consulted to another doctor and he precribed zifi 50 ,we had stool test as well and it was normal without Smeel ,PLease Suggest .