Abstract: The present invention provides a method for treating wounds and diseases in mammals, caused by mammalian cells involved in an inflammatory response, by altering indigenous in vivo levels of peroxynitrous acid, and salts thereof. The method comprises contacting the mammalian cells with a therapeutically effective amount of a reactive oxygen species mediator, wherein the reactive oxygen species mediator is selected from the group consisting of pyruvates, pyruvate precursors, ?-keto acids having four or more carbon atoms, precursors of ?-keto acids having four or more carbon atoms, and the salts thereof, wherein mediation of reactive oxygen species results in mediation of peroxynitrous acid. The present invention further provides a pharmaceutical composition for treating wounds and diseases in mammals, caused by mammalian cells involved in an inflammatory response, by altering indigenous in vivo levels of peroxynitrous acid, and salts thereof.