2010). On the other hand, it has been suggested that indomethacin induces gastric damage by inhibiting the release of protective factors like cyclooxygenase-1 (COX-1), prostaglandin E2 (PGE2), bicarbonate and mucus, besides reducing antioxidant mechanisms while increasing oxidant factors (Halici et al. 2005). Independent of original mechanism, both models could be well-accepted as oxidative stress-induced stomach disease, since the mechanism of ulcer induction might be mediated by reactive oxygen species (ROS) (Oyagi et al. 2010). The gene discussed is PTGS1; the disease is ulcer disease.