Since prostaglandins were first proposed as mediators of in- flammation some eight years ago, there have been a variety of arachidonic acid metabolites discovered including the thromboxa- nes, prostacyclin, prostaglandin endoperoxides and lipoxygenase products such as SRS-A. All of them have subsequently been shown to have significant and specific biological activities not only in inflammatory responses but also in other physiological pro- cesses. The explosion of research in this area has been an indi- cation of the importance of this field but has also meant that it is time for an...