Covering: July 2005 to June 2007. Previous review: Nat. Prod. Rep., 2006, 23, 464–496.

Nature abounds with a great number of natural products containing five-membered heterocyclic subunits, such as imidazoles, oxazoles and thiazoles, and their corresponding saturated imidazolines, oxazolines and thiazolines. These naturally occurring metabolites often exhibit pharmacologically important biological activities. In this review, the isolation, biological activities, chemical synthetic studies, and biosynthetic pathways of these natural products are summarized.