And what else???
A 3yo is likely to have 3 diarrhea
illnesses /yr due to simple viruses & most will be associated with mild fever
If the kid is playful most of the time & taking fluids well enough to pee every 6 hours you may be able to handle it at home. If the kid has bloody material in the stools, acts tired & whiny most of the time or begins to refuse fluids, the kid should be examined.