Cyclo-oxygenase (COX) is a family of enzymes regulating the conversion of arachidonic acid to prostaglandins. COX-II is an inducible enzyme, which may be upregulated when there are stimuli such as inflammation or hypergastrinaemia. Despite radical surgery, patients with stomach cancer of advanced stages often have a poor prognosis. Reported survival in those with diseases of stage IIIa or above is less than 40%. Methods to improve patients outcome have been explored for decades with little success. In the light of current understanding on the relation between COX-II and stomach cancer, selective COX-II inhibitor may be used as a novel adjuvant therapy after gastrectomy to prevent recurrence of gastric carcinoma. The advantages of COX-II inhibitors are being relatively non-toxic with minimal side effect.