NaCLO3 was not used by Tesla. The purpose and effect are similar to use of NaCLO2. All these products, peroxide,ozonated olive oil, NaCLO2, NaCLO3 etc, are oxygenators. They all release oxygen, but in slightly different ways. As rat killer Common Table Salt is also quickly lethal if excess is consumed.
Peroxide is also lethal if consumed in excess.
Peroxide is a Hazardous material. For making homemade mini-bombs as a child. Strong Peroxide is used as Rocket Fuel. It really puts one into orbit.