Background: Eucalyptus oil often used for medicinal purposes. Aims: The Eucalyptus oil gastro protective impact investigated against gamma-rays-exposure-induced gastric ulceration in rats. Materials and  Methods: Thirty-two rats were divided equally into 4groups; control, Eucalyptus oil (100mg/ kg), gamma-rays (7Gy) and Eucalyptus oil plus gamma-rays treated groups. The stomach histopathology samples were examined. The levels of malondialdehyde, reduced glutathione, superoxide dismutase, tumour necrosis factor-α and the interleukin-1β were assessed. Results: The stomach histopathological examination revealed that pre-treatment with Eucalyptus oil enhanced regeneration of mucosal crypt cells. The results revealed a decreased level of stomach malondialdehyde, inflammatory markers, increased levels of stomach antioxidants markers in Eucalyptus oil plus gamma-rays treated group. Conclusion: Eucalyptus oil ameliorates gamma-rays-induced gastric ulceration that could attribute to its antioxidant, anti-apoptotic and radioprotective activities.