I experience terrible nausea. Sometimes it is caused by pain, sometimes it is caused by one of my medications, and fatigue will upset my stomach beyond belief.
My primary care physician prescribed Prilosec, to be taken about 30 minutes before taking my strongest pain medication, but that does not ease the nausea I feel at other times, so I keep lemons in the house.
I find eating a lemon, with a touch of salt helps a lot, but not everyone can tolerate lemons eaten this way!