You have the cans and bottles of soda too - Mexican Coca-Cola is great, better than what we get in the states.
Frozen drinks are okay as long as you get them at the better known places. In other words I don't worry about getting a frozen margarita at Carlos n' Charlies or Senor Frogs, or Fat Tuesdays, because they use filtered water (or so they say - I have never gotten sick from them). However I wouldn't get a frozen margarita from Jorge's Bar and Grill on the side street.
Our doctor advised to take CHEWABLE pepto bismal pills every day the entire time in Mexico. I can't remember if he said 3 or 4 times daily. This advice was given for an AI land vacation, so applied more than on a cruise.
I still followed all recommendations about not drinking any tap water anywhere, but did eat everything offered at reputable places such as Hard Rock, etc. and at the hotel. Also had frozen drinks. I did get careless in Mexico once and ordered a drink on ice at a bar, and was VERY sick the next day.
thank you for the wealth of info here...was a bit nervous, we've traveled the caribbean twice, but never mexico on vacation. my hubby goes on business, but eats w/reps @ reputable places...much appreciated.