I don't think you can stay away from it. I have a stomach of steel and I still got sick. I didn't drink any tap water or have any mixed drinks at clubs. Drank beer and bought a bottle of my own hard alcohol and went that route. The worst thing about my trip to Cancun was the food. Absolute CRAP. The hole in the walls were crap, the hotel food was crap, the american places were crap, the water taste like the plastic bottle, the soda is flat, I was ready to kill myself pretty much. I think i lost like 10lbs when there. The only good place we ate at was Lorenzillos. Probably the best restaurant in all of cancun. Good Luck!