Good formula

Please recommend me a good formula. My son have been drinking few brands and some brand after drinking he will end up getting diarrhea and some brand were eczema or rashes. Im not sure if he's lactose intolerant so i tried isomil soy milk. Everything was fine but after few weeks he suddenly got diarrhea again after drinking. So I changed to goat milk (karihome) its good but he doesn't like it! End up he will just drink a little in one day. My son is 1year 5months.