Gastric ulcer (GU) is among the peak prevalent syndromes. This study investigates the defensive properties of Achillea fragrantissima (Forssk.) Sch.Bip. extract (AFE) against ethanol-induced stomach lesions. Twenty-eight rats were allocated into negative control, positive control, AFE + ethanol, and omeprazole ethanol. In serum and gastric homogenates, oxidative stress displays (e.g., malondialdehyde (MDA), decreased glutathione (GSH), superoxide dismutase enzyme (SOD), and catalase enzyme (CAT)) and inflammatory parameters (e.g., tumor necrosis factor-alpha (TNF-α)) were estimated. GU markers (gastric lesions, ulcer index (UI), pH) were evaluated, and gastric histopathological examinations were performed. The positive control cluster exhibited severe gastric mucosal injuries, reduced stomach mucus secretion, and pH of gastric content. Furthermore, AFE-pretreated rats displayed meaningfully increased periodic acid-Schiff (PAS) countenance in their stomach epithelial layers. Pretreatment with AFE reduced stomach lesions, UI, MDA, and TNF-α levels, while mucus, pH, CAT, GSH, and SOD levels increased. Stomach examination showed significant improvement in gastric mucosa reduced edema and leukocyte infiltration of the submucosal level in pretreatment with the AFE and omeprazole groups versus the ethanol group. Additionally, AFE extracts increase the intensity of the stomach epithelium's PAS. The acute toxicity experiment with an advanced dosage of 5 g/kg AFE did not exhibit any signs of toxicity in the rats. In conclusion, the AFE reduced the effect of ethanol on the gastric mucosa, which may be due to its antioxidants and anti-inflammatory properties.