Widely used in Europe for many years; Ozone (O3) is a highly active form of oxygen. Because it has powerful antiviral properties, it is also used in treating AIDS. In the body, ozone gives off O which kills viruses and bacteria. It also creates an oxygen-rich environment that may force cancer cells to shift from an anaerobic metabolism to an aerobic, or oxygen-based, metabolism. Ozone also produces molecular oxygen (O2), in the same way that hydrogen peroxide does.