The thiamine actions were investigated about thiamine anhydride sulfoxide (TAO) and thiamine anhydride sulfone (TAO2) which were obtained by oxidating thiamine anhydride with H2O2. It was found that though 500λ of TAO and TAO2 were respectively administrated to the rats which were feeded with thiamine deficient diet, each substance did not show the thiamine action and that LD50 of TAO2 was lowe than that of thiamine.
