The evening primrose oil (EPO) commercially known as Callanish evening primrose oil (omega-6 polyunsaturated fatty acid) is linoleic acid (LA) and gamma-linolenic acid (GLA)-enriched oil obtained from the seeds of Oenothera biennis L. (Fam. Onagraceae). EPO was investigated for its ability to protect the gastric mucosa against injuries caused by pylorus ligation, non-steroidal anti-inflammatory drugs (NSAIDs; aspirin, indomethacin and phenylbutazone), hypothermic restraint stress and necrotizing agents [0.6 M HCl, 0.2 M NaOH, 25% NaCl or 80% (v/v) aqueous ethanol]. It was administered by gastric intubation at doses of 5 and 10 ml/kg body weight to rats fed standard chow diet. An additional group of animals was given the same amount of corn oil in each experimental model studied. The results showed that EPO at the doses of 5 and 10 ml/kg body weight provided significant protection in various experimental models used. It produced a significant inhibition of gastric mucosal damage induced by pylorus ligation, NSAIDs, or hypothermic restraint ulcers. EPO also had a marked cytoprotective effective effect against all necrotizing agents used in this study. The results suggest that EPO rich in LA and GLA possesses both antisecretory and anti-ulcerogenic effects.