Ibuprofen inhibits Cox (cyclooxygenase) selectively, targeting Cox-1 (PGH synthase-1) with an IC50 of 13 μM, and Cox-2 (PGH synthase-2) with an IC50 of 370 μM. Ibuprofen is useful as a nonsteroidal anti-inflammatory research chemical. Ibuprofen is reported to inhibit the netrophil-dependent edema response of rabbit skin to C5a/PGE23.