Antiulcerogenic activity of crude ethanolic extract of Celtis iguanaea leaves (CEE) was observed with experimental models such as ethanol, indomethacin, stress and pyloric ligation-induced gastric ulcers. Results obtained from indomethacin-induced ulcer showed the hexane fraction (HF) as the active fraction of CEE. This fraction inhibits the gastric acid secretion, increasing the gastric pH, decreasing the gastric acidity and total gastric contents. Neither the CEE nor the HF alters intestinal motility, thereby excluding a cholinergic antagonist mechanism. Further studies need to be conducted with HF in order to elucidate the active principle and the pharmacological mechanism involved.