Regular hand washing is the best defense, because the microorganisms that cause diarrhea are easily passed from hand to mouth.

Call the doctor if your toddler has diarrhea and doesn’t seem to be improving after 24 hours. Also call if your child has diarrhea and any of the following :

While rarely serious when treated properly, diarrhea can send your toddler to the hospital if he becomes dehydrated, so your first concern should be giving him enough liquids.

Some bacterial infections clear up on their own, but some, like that from the E. coli that can be found in undercooked meat or other food sources, can be very serious. So if your toddler has these symptoms, take him to the doctor. She’ll examine him and probably evaluate a stool culture for signs of a bacterial infection.

The list of possibilities is long. It could be caused by a viral or bacterial infection. It might also be the result of a parasite, a course of antibiotics, or something he ate :