Chaetomin is an epidithiodioxopiperazine metabolite first isolated from Chaetomium cochliodes by Waksman and Bugie in 1944 as an antibiotic. Its structure was resolved in the 1970s comprising a non-symmetric bis-epidithiodioxopiperazine with both hemispheres having a core N,N’-dimethyldiketopiperazine linked by a bisulfide bridge. Chaetomin is an important chemo-taxonomic standard for characterising the genus Chaetomium. Chaetomin is a potent antitumor agent, inhibiting hypoxia-inducible transcription. Chaetomin is used extensively as a molecular reagent and is the subject of over 150 citations in Scifinder.