The whole story of the development of the sulfa drugs is pretty eye-opening, and is well-told in this popsci history book by Thomas Hager (2006), which also cov

The whole story of the development of the sulfa drugs is pretty eye-opening, and is well-told in this popsci history book by Thomas Hager (2006), which also covers this toxic poisoning episode: https://en.wikipedia.org/wiki/The_Demon_Under_the_Microscope https://en.wikipedia.org/wiki/The_Demon_Under_the_Microscope One fascinating aspect of this is that Bayer originally tried to convince the world that their patented derivative of sulfonamide, Prontosil (note nitrogenous ring additive) was the one that worked. https://en.wikipedia.org/wiki/Prontosil https://en.wikipedia.org/wiki/Prontosil It turned out that the non-patentable sulfanilamide was the actual active species, which Bayer probably knew but kept secret because, well, patents and market share and so on: https://en.wikipedia.org/wiki/Sulfanilamide https://en.wikipedia.org/wiki/Sulfanilamide