(Written upon my return from Mexico.)
Last post--2 months ago--was about traveler's diarrhea. Looks like my friend was right. The best solution was to drink *lots* of clean water and wait for the body to acclimate.
After 10 days of misery, my body built the necessary immunities and the diarrhea abruptly ceased. I was almost ready to go the oral antibiotics route, but was dissuaded by the possibility of wiping out all the beneficial bacteria in the gut, along with the single offending bacteria.
I also maintained a daily regimen yogurt (a pro-biotic food), avoided anything that could have been washed in local water and took supplemental fiber each AM.