Deworm

hello mummies, my son is 10month old, whenever I feed him he always throw up, some said its worm that I need to deworm him, others said I should change his food which I have tried but still the same thing, I read through google that he's not up to the age of deworming till he's a year old even the last time we were with our doctor, she said he's too young for it, then he was 9month old. pls any advice on how to go about this?