The present invention provides a use of a substance in the preparation of a product for treating chronic atrophic gastritis, protecting gastric mucosa, treating gastric precancerous lesions, blocking transformation of gastritis into cancer, and preventing occurrence of gastric cancer, the product being one selected from a medicament, a healthcare product and a foodstuff, and the substance being selected from the group consisting of: nuciferin, a nuciferin derivative, a lotus leaf extract, and a mixture of at least two selected from the above substances. The use includes at least one of treating chronic atrophic gastritis, protecting gastric mucosa, blocking transformation of gastritis into cancer, treating gastric precancerous lesions, and preventing occurrence of gastric cancer. In vitro experiments showed that nuciferin can block transformation of gastritis into cancer and cell proliferation. In vivo experiments showed that nuciferin and lotus leaf extract can treat atrophic gastritis in rats (especially chronic atrophic gastritis with intestinal metaplasia or dysplasia), protect rats from gastric mucosal damage and inhibit abnormal proliferation of gastrointestinal stem cells in Drosophila. Clinical tests indicated that lotus leaf extract can improve symptoms and objective indicators in patients with atrophic gastritis or gastric precancerous lesions.La présente invention concerne l'utilisation d'une substance dans la préparation d'un produit pour traiter la gastrite atrophique chronique, protéger la muqueuse gastrique, traiter des lésions précancéreuses gastriques, bloquer la transformation de la gastrite en cancer, et empêcher l'apparition d'un cancer gastrique, le produit étant un produit choisi parmi un médicament, un produit de soins de santé et un produit alimentaire, et la substance étant choisie dans le groupe consistant en : nuciférine, un dérivé de nuciférine, un extrait de feuille de lotus et un mélange d'au moins deux substances choisies parmi les sub
