Hello dear,my name is dr,Dorina Gurabardhi.I understand your concern.Antibiotics can upset the normal bacteria balance in the gut, causing diarrhea. Some advices that I can give to you are: -avoid foods that commonly trigger diarrhea -Probiotics May Relieve Diarrhea -give to your son water to stay hydrated and replace any fluids lost to diarrhea Hope my answer was helpful,if you have any other question I will be glad to answer,thanks!