Cool Rhino Cooling Water / O2 Cooling Water (350ml x 1) Traditionally used to relieve fever and body heatiness. The key ingredient in Cool Rhino is deionized water that comes along with 100% natural ingredients such as Gypsum Fibrosum and Calcitum that are cooling by nature to help reduce “heatiness” of the body. Cool Rhino O2 is enriched with additional oxygen to improve the amount of oxygen carried by red blood cells.