Background & Aims: Achillea is a plant widely used in traditional medicine for gastrointestinal disorders. The aim of this study was to investigate the preventive effect of Achillea wilhelmsii hydro-alcoholic extract on indomethacine-induced gastric ulcer in rats.

Materials & Methods: It was an interventional study and done on six groups of male Wistar rats (n=8 in each group). Three doses of Achillea wilhelmsii extract (200, 400 and 800 mg/kg) were given orally to three groups for three days. After the third day the indomethacine in methyl cellulose (1%) suspension were given orally to the rats and the animals were anesthetized after 6 hours and the pylorus ligatated for one hour. Then the gastric juice extracted and gastric acid titrated by NaOH. The preventive ratio, gastric mucus secretion, NP-SH compounds and lipid peroxidation were measured.

Results: Achillea wilhelmsii extract clearly prevented indomethacine- induced ulcer. The Achillea wilhelmsii extract reduced gastric acid secretion by 400 and 800 mg/kg doses compare to the indomethacine group. The extract increased gastric mucus which was significant by 800 mg/kg dose. NP-SH compounds increased significantly by 200 and 800 mg/kg doses in comparison the indomethacine group. Lipid peroxidation noticeably reduced by all three doses.

Conclusion: The Achillea wilhelmsii extract showed obviously preventive effect on indomethacine-induced gastric ulcer. Although the potency of the extract on inhibition of gastric acid secretion and increase of gastric mucus secretion are important in this preventive effect but antioxidant effect of the extract is more prominent.