Cyclo-oxygenase (COX) is a family of enzymes regulating the conversion of arachidonic acid to prostaglandins. COX-II is an inducible enzyme, which expresses excessively when there are stimuli such as inflammation or hypergastrinaemia. Up to 40% of patients with stomach cancer are found to have disseminated disease during surgical exploration. While palliative resection could offer a marginal benefit in the survival of these patients, almost all patients will die of progression of disease within a short time span. Palliative chemotherapy has been used in the past. However, there is no evidence that the chemotherapy can confer any survival advantages, and the side-effects and toxicity of the treatment may indeed compromise the quality of life of these patients. With a better understanding of the relation between COX-II and stomach cancer, it may be possible to suppress the progression of the residual cancer cells after the palliative resection by giving the patients selective COX-II inhibitors.