It has been suggested that creatine exhibits antioxidant properties towards reactive oxygen species and free radicals, but whether creatine may also neutralize reactive chlorine species is unknown. Hypochlorous acid is produced during phagocytosis and is known to react indiscriminately with proteins, damaging side chains and cross-linkages. The purpose of this research project is to determine whether or not creatine can deactivate hypochlorous acid under biological conditions. Preliminary studies have shown that a reaction does occur in the seconds to minutes time scale, however the reaction appears to behave differently under acidic conditions than it does under basic conditions. Furthermore the production of one or more gases is observed under some conditions. Analysis of the products (uncharacterized to date) has revealed the presence of active chlorine, suggesting that creatine does not ”deactivate” the chlorine atom of hypochlorous acid. If allowed to react in the absence of a buffer, the reaction mixture exhibits a large decrease in pH, suggesting a significant production of H⁺ ions in the process. A summary of experimental procedures, results and conclusions about this complex system will be the subject of this presentation.