Really depends on what sets you off.You might try white grape juice (is sweet but you can dilute it, with a sparkling water if you tolerate some carbonation).Watch the diet things as some diet sweeteners bother some people, but the high fructose corn syrup isn't any better.There are some flavored waters that may be worth trying, some don't have sugar added and I think some don't have other sweeteners either.Mint tea is usually good and you might find some of the bottled teas you can have (just check what they sweeten it with).If you like lemon or lime you can put a slice or two in the water, or a few slices of cucumber.