A method is provided for rapidly screening candidates for precancerous atrophic H. gastritis by visualizing the presence of a hypoacidity condition of the gastric mucous membrane by applying droplets of an indicator to the stomach wall which indicator undergoes a marked color change in the presence of a hypoacidic condition and then detecting immediately the presence of that color change. The indicator employed is bromocresol green, bromophenol blue or bromochlorophenol blue.
