My 9-month-old has a sensitive stomach...advice?

I have a 9 month old with a super sensitive stomach… We just now finally found a formula that works for him.It’s like every other week he has acidic poop when we try new foods.Is there some type of doctor that we should take him to? Or is this just something we got to get through on our own?Approve

I don’t have any experience with a little with such a sensitive stomach but start with your pediatrician. Perhaps they can refer you to a gastroenterologist.