Bisphenol A induced gastric ulceration and decreased the volume of gastric juice, prostaglandin E2 (PGE2), reduced glutathione (GSH) and interleukin 10 (IL-10) contents, superoxide dismutase (SOD) activity, and proliferating cell nuclear antigen (PCNA) protein in stomach tissues, while increased the titratable acidity, malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) contents, and caspase-3 and NF‐κB proteins in stomach tissue. The gene discussed is SOD1; the disease is gastric ulcer.