Deuterium Oxide (heavy water) is a stable, non-radioactive isotopic form of water. The heavy water is used as a moderator of neutrons in nuclear power plants. In the laboratory, heavy water is employed as an isotopic tracer in studies of chemical and biochemical processes. Deuterium oxide acts as a true temperature-modifying agent. It protects mammalian cells against hyperthermic damage. Plant cell biologists had made a similar observation. Regarding human health, deuterium oxide has a wide range of proposed applications, such as therapeutic agent against human pancreatic cancer, determination of total body water (TBW), and enhancement of thermal stability of macromolecules, cells and tissue. Other applications are: treatment of hypertension, treatment of virus-based diseases of the respiratory tract and treatment of herpes virus-based diseases of the skin.