For vomiting type upset, you can give them Pepto Bismol. I usually give them the tablets dipped in peanut butter, b/c the bright pink liquid isn't always a favorite flavor and it stains....
I've heard that Pepcid AC works, too, but I'm not sure on amounts.
You could call your vet and ask how much on either med.
For diarrhea, give them canned pumpkin. (Not pie filling that is already spiced, but just plain pumpkin.) They usually like the taste and it will stop the poops quickly! Start with a nice spoonful. If they are still going try another. It should take care of the problem.
My vet always recommends feeding plain rice with a little chicken broth instead of kibble until the tummy is better. Add in a little meat like chicken or lean hamburger as they are feeling better. Then start adding kibble.