We have been there numerous times and have never had any issues, one trip my wife was going very heavy on salad and started some minor stomache issues, she now stays away from salad and has not had an issue since. Each person is different, I have never had any issues. Some people also over indulge in drinking and get dehydrated and have stomache issues.
Remember if you are not a drinker at home do not try and get your fill because its all inclusive or you will be sick.
During our trips we have been off the resort to some dance clubs and a few local hangouts and have never had any safety issues. Just remember you are the visitor keep your senses of whats around you and do not do what you would not do at home.