Naproxen exerts an anti-inflammatory and antifibrotic effect in mouse model of bleomycin-induced lung fibrosis. Naproxen also downregulates TGF-β levels and Smad3/4 complex formation. Naproxen is shown to inhibit the time-courses of pain, fever and PGE2 with similar potencies (IC50=27, 40, 13 μM).