What can i give my 5 year old with an upset stomach?

Fluids: When kids have upset stomach, the best thing to do is keep them hydrated but don't push anything else that will cause further upset. So the old sips of water, popsicles, very dilute juice, flat 7-up, all work. Using anti-diarrheals or other stomach meds usually just end up making matters worse in the long term. If they are really nauseated, your doctor can prescribe anti-nausea meds - they work!