What's a good alcoholic beverage for those with a sensitive stomach?

My girlfriend drinks, and has done so for many years without a problem. Lately, however, she’s complained of being nauseous with an upset stomach after very little drinking. That’s the only time she complains about it too, so I think it just has to be the alcohol. It was with wine two times, and rum the next.

I suggested switching to beer or something mixed with tonic and/or gingerale. Does this sound right? or any other suggestions?