The aim of the current study is to evaluate the anti‐inflammatory effect of Thymus fontanesii with chemotype carvacrol and its gastroprotective effect against ethanol‐induced gastric ulcer model by using the image analysis method by means of the ImageJ® software. The chemical composition of the essential oil was analyzed by gas chromatography/mass spectrometry and the acute toxicity was evaluated. The anti‐inflammatory activity was assessed by two methods such the Carrageenan‐induced paw edema in mouse at dose of 500 mg/kg and topical inflammation induced by 12‐O‐tetradecanoylphorbol‐13‐acetate at dose of 03 and 10 mg/ear. The antiulcer activity of the essential oil of the studied plant was assayed at dose of 250 and 500 mg/kg, by ethanol‐induced gastric ulcer model in rats, showed a significant decrease of gastric lesion areas. The obtained results confirm the anti‐inflammatory and the gastroprotective activity probably attributed to its main compound, carvacrol which support the traditionally uses of the studied plant. Practical applications The Thymus fontanesii, which is an endemic plant to Algeria and Tunisia, is traditionally used in the treatment of inflammation and fever. This study revealed that the T. fontanesii essential oil with chemotype carvacrol possesses significant anti‐inflammatory activity, side by side with the antiulcer activity as the Ethanol‐induced gastric ulcer model showed a significant decrease of gastric lesion areas. Thus, it stands as a promising candidate for further investigations in this area.