Methylene blue (methylthionine chloride U. S. P.) has been shown by Sahlin,1Eddy,2Brooks,3Hug4and Hanzlik5to antagonize the action of cyanide in animals, and recently it has been successfully used by Geiger6in the treatment of cyanide poisoning in a man. Hug4has demonstrated that sodium nitrite is a better antidote than methylene blue in dogs. He7and Wendel,8working independently, have offered a new view concerning the antagonism. We have investigated both methylene blue and amyl nitrite in cyanide intoxication and have found the latter to be more efficient than the former. The differences in the results appear to be so decisive as to merit a presentation to those who are interested in the subject. It should be understood that we make no claims to originality in this study but merely announce our confirmation of Hug's and Wendel's