Ethanol : water (1:1) (EWRC), ethanol (ERC), methanol (MRC) and water (WRC) extracts of Ramalina capitata (Ach.) Nyl. (R. capitata) significantly reduced the gastric lesions induced by indomethacin (IND). The highest gastroprotective effect (66.6%) was shown by EWRC at a 200 mg/kg dose. IND caused significant decreases in the levels of glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD) and reduced glutathione (GSH). However, EWRC exhibited a significant antioxidant activity against oxidative damage in stomach tissues, increasing the levels of GPx, GST, SOD and GSH. However, catalase and myeloperoxidase levels increased by the administration of IND were found to be lower in EWRC administrated groups. Furthermore, all extracts tested exhibited significant in vitro antioxidant activity. These results indicate that the extracts of R. capitata have gastroprotective effects against IND-induced gastric ulcer, which could be attributed to its reducing effect of oxidative damage and of neutrophil infiltration into gastric tissues.