Suggest Treatment For Baby Passing Watery And Greenish Yellow Stools

My 4 month old son was having nasal congestion since 1 month. Dr started on tsb monocef 50 mg half twice a day along with syp cetrizine and ascoril ls drop. After taking that he started to have loose stools 6 times a day now he is on oflomac m and derolac powder. Still he passes froathy watery greenish yellow stools. On breastfeeding and nan pro 90 ml at night. What to do