Different phyla and different oceans are sources of linear peptides in the aeruginosin family which comprise a central hydroxy- (or dihydroxy-) octahydroindole carboxamide core unit onto which unusual amino acids are appended. The aeruginosins exhibit varying degrees of inhibitory activity against serine proteases, including factor II (thrombin) and factor VIIa of the blood coagulation cascade. In their Review on page 1202 ff., S. Hanessian et al. provide an overview of the chemical and biological properties of the aeruginosins as well as the natural sources of these compounds, their total syntheses, and structure revisions.