To find an inhibitor of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) that rapidly metabolises Prostaglandin E-2 (PGE(2)) as a mediator of wound healing, we examined seven flavonoids for this role. 7,3',4'-Trimethoxyflavone (TMF) had the lowest IC50 value of 0.34 A mu M for 15-PGDH inhibition but > 400 A mu M for cytotoxicity, indicating a high therapeutic index. TMF elevated PGE(2) levels in a concentration-dependent manner in both A549 lung cancer and HaCaT cells. It also significantly increased mRNA expression of multidrug resistance-associated protein 4 (MRP4) and of prostaglandin transporter (PGT) slightly in HaCaT cells. In addition, TMF facilitated in vitro wound healing in a HaCaT scratch model, which was completely inhibited by adding both 15-PGDH and NAD(+) as cofactor, confirming the involvement of PGE(2) in its wound healing effect. TMF with a high therapeutic index can facilitate wound healing through PGE(2) elevation by 15-PGDH inhibition.