You can use any beverage in the CamelBak Bottle, however we do not recommend the use of carbonated beverages. Due to the construction of the bottle (and the possibility of creating a pressurized environment inside of it), using carbonated beverages in the CamelBak bottle can sometimes create a similar experience to opening a can of soda that has been shaken up repeatedly. If you want to use carbonated beverages with the CamelBak Bottle, we recommend that you remove the straw and drink via “tip and sip”. I copied this off a manual I found online about Camelbak bottles.