Nausea: ginger beer or ale, ginger or mint teas or candies
Heart burn: non-caffeinated non-alcoholic carbonated drink
Gassiness: unsweetened tea
Diarrhea: water, tea
Constipation: non-caffeinated drink
If upset stomach is accompanied by loss of appetite, bleeding from mouth or rectum, or rigid or painful belly, you need to be seen by a doctor.