Baby diarrhea?

Ariel • #AutismMom #BoyMom

My 1 month old has diarrhea. My mother gives him rice cereal I told her not to because he was born at 35w so he's a preemie. His poop had been watery lately. I was in the hospital for a week due to a surgery I had. Anybody know what causes diarrhea in a 1 month old?