Decursinol is one of the coumarins purified from the dried roots of Angelica gigas Nakai (Umbelliferae) and has various pharmacological effects including an analgesic property. Although aspirin is widely used to reduce pain and inflammation, aspirin-induced gastric damage remains the major limitation to its use. Therefore, the anti-ulcer activity of decursinol in aspirin-induced gastric ulcer in mice was examined. One group of mice was treated orally once daily with aspirin (300 mg/kg) and another group was co-administered with decursinol (10, 25, 50, and 100 mg/kg) and aspirin (300 mg/kg) orally once daily for 5 consecutive days. On day 6, the gastric mucosae were examined. Animal groups co-administered with decursinol and aspirin exhibited a dose-dependent reduction of gastric damage against aspirin-induced gastric ulceration. The extent of inhibitions for the respective doses employed was 11.1, 15.8, 50.3, and 70.4%, respectively. These results suggest that combination therapy with aspirin and decursinol may be useful to alleviate pain and inflammation without major gastrointestinal side effects.