Mutilin is minor metabolite of the pleuromutilin family, originally isolated from Pleurotus mutilus. Mutilin is formed by hydrolysis of the hydroxyacetyl ester of pleuromutilin, and is a degradation product and in vivo metabolite of pleuromutilin. Interest in mutilin has focused on its potential as a substrate for generating unique metabolites via biosynthesis to provide a broader range of targets for semi-synthetic modification.