We've been traveling to Mexico once or twice a year since 2000. In all that time, Jim and I got Traveler's Diarrhea only once. On that occasion, we made the mistake of eating grapes from the fruit basket left in our room. Two days later, we were sick with fever, headache, and diarrhea that lasted 24 hours.
Since that episode, on our doctor's recommendation, we now chew 2-3 Bepto Bismol tablets before every meal while on any international trip. We also only eat cooked or peeled fruits and vegetables. It's a strategy that's worked well for us for the past 6-7 years.
So last night, I couldn't believe my numerous trips to the bathroom were caused by last week's vacation, especially since Jim is absolutely fine. But, in the light of day, I have to wonder. Whatever the cause, I'm just grateful I wasn't going through this during the flight home!