Mycophenolate mofetil is an established anti-proliferative and immune-suppressive agent that minimizes the proliferation of inflammatory cells by interfering with nucleic acid synthesis. Herein, we report our discovery of the prostaglandin inhibiting properties of MMF, which offers new applications for the drug in the treatment of inflammatory diseases. The estimated values of IC.sub.50 MMF.sub.COX-1 , IC.sub.50 MMF.sub.COX-2 , and IC.sub.50 MMF.sub.5-LOX were 5.53, 0.19, and 4.47 [micro]M, respectively. In contrast, mycophenolic acid (MPA) showed slightly stronger inhibition: IC.sub.50 MPA.sub.COX-1 , IC.sub.50 MPA.sub.COX-2 , and IC.sub.50 MPA.sub.5-LOX were 4.62, 0.14, and 4.49 [micro]M, respectively. These results indicate that MMF and MPA are, respectively, 28.6 and 33 times more selective for cyclooxygenase-2 than for cyclooxygenase-1, which implies that MMF would have less impact on the gastric mucosa than most nonselective, nonsteroidal anti-inflammatory drugs. Furthermore, MMF provided dose-dependent relief of acute inflammation in the carrageenan-induced rat paw edema test, with results comparable to those of celecoxib and indomethacin. Molecular dynamics simulations indicated that the MMF bond with COX-2 was stable, as evidenced by a low root-mean-square deviation of atomic positions, complementary per-residue root-mean-square fluctuation, and 0-4 hydrogen bonds during the 50-ns simulation time. Therefore, MMF provides immune-suppressing, cyclooxygenase-inhibiting, and inflammation-relieving properties. Our results indicate that MMF can be 1) repositioned for inflammation treatment without the need for further expensive clinical trials, 2) used for local acute inflammations, and 3) used as a sparing agent for other steroid and non-steroid anti-inflammatory medications, especially in topical applications.