Cesium chloride is a colorless salt made from cesium, a metal. Its formula is CsCl, and it can be radioactive or non-radioactive. Non-radioactive cesium chloride has been used experimentally as a cancer treatment in conjunction with other supplements and a special diet.
In at least one study, the therapy was effective, with a 50 percent recovery rate. CsCl is also used to aid in the diagnosis of heart attacks. Cesium chloride is also used in cathode ray tubes, welding, excimer lamps and high-temperature solders. Non-radioactive CsCl is not particularly toxic to humans or animals, though breathing in the powder can cause irritation of the mucous membranes.