Initially suspecting that since CO poisoning and methemeglobinemia are not the same, methylene blue might not work in CO cases, I did about three seconds of web

Initially suspecting that since CO poisoning and methemeglobinemia are not the same, methylene blue might not work in CO cases, I did about three seconds of web searching and found a 1933 paper about an experiment (on animals) showing methylene blue to be effective in CO poisoning.