Girls, hello everyone. Please help, my 8-month-old baby tried kefir ye…

Girls, hello everyone. Please help, my 8-month-old baby tried kefir yesterday, he liked it, but his tummy seems unable to cope. There's no diarrhea, but watery stool, 4-5 times a day. I breastfeed him, water, what else can we give him from medicines to help his stomach? The child behaves as usual, cheerful, plays, a little capricious, but she still has upper teeth coming in.