Delta(12)-prostaglandin J(2) is a potent inhibitor of influenza A virus replication.

9-Deoxy-Delta(9),Delta(12)-13,14-dihydro-prostaglandin D(2) (Delta(12)-PGJ(2)), a natural cyclopentenone metabolite of prostaglandin D(2), is shown to possess therapeutic efficacy against influenza A virus A/PR8/34 (H1N1) infection in vitro and in vivo. The results indicate that the antiviral activity is associated with induction of cytoprotective heat shock proteins and suggest novel strategies for treatment of influenza virus infection.