Does indomethacin activate healed gastric ulcers in the dog?

Effects of indomethacin on healed partially healed gastric ulcers in the dog were studied. Gastric ulcers were produced by submucosal injection of 1 ml of 40% acetic acid solution into the bordering area of the fundus and antrum of the stomach. Indomethacin, 20 mg/kg, was given orally once daily for 5 days beginning on the 50th day after ulceration. While erosions or deep ulcers were produced by indomethacin, healed or partially healed acetic acid ulcers were not aggravated. Mechanisms involved in this strong resistance of healed ulcers to the ulcerogenic agent remain to be determined.