Delonix regia, commonly called Flame Tree or Flamboyant (locally, Gul Mohor) is a common tree traditionally used to treat various diseases like gastric problems, body pain, rheumatic pains of joints and wound healing. Here, we carried out biological profiling of Delonix regia as antiulcer agent. Antiulcer activity of the ethanol extract from stem bark was evaluated on pylorus ligation and indomethacin induced ulcer in Wistar albino rats. Ethanol extract from stem bark of D.regia was administered at the doses 100, 200 and 400 mg/kg/day, p.o. for 7 days. Ulcer index, gastric pH, volume, free acidity, total acidity, total carbohydrate (TC), protein (P), mucin content (TC/P) and gastric mucus were evaluated in pylorus ligation model, while ulcer index, malondialdehyde, GSH, PGE2, and gastric mucus were estimated in the indomethacin induced ulcer model. Ex vivo assay for the activity of H+/K+-ATPase was also done. The results showed significant inhibition on H+/K+-ATPase in a dose dependent manner and comparableto their respective positive control group of rats demonstrating that ethanol extract of stem bark of Delonix regia possesses significant antiulcer properties.