where is the abdominal pain. Is it all over? when did it begin and how severe is it. Is this an ongoing problem or a new problem. when did the vomiting begin and how many times. when did the diarrhea start? is there blood in the diarrhea?
I certainly think he has a stomach virus that has been going on for several days. It should be getting better soon. Whether it is from the taco, or just exposure to someone who had a stomach virus, it is hard to tell. If he is gassy, avoid gassy vegetables and dairy until he feels better.
Peptobismal may help, but I think that you are better off getting an antigas medicine that contains simethicone, like children's gasX. Keep the diet on the plain side until he starts to feel better. If the stomach pain worsens, moves to the right lower side of his belly or develops fever, or blood in stool, then he needs to be seen by his doctor.
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