Objective: To observe the effect of volatile oil of amomum (VOA) on the expressions of mastocarcinoma-related peptide (PS2) and platelet activating factor (PAF) in helicobacter pylori-associated gastritis (HPG) and to analyze its potential mechanism. Methods: Eighty patients with HPG were randomly assigned to two groups, 42 patients in the treated group treated with 0.5 mL VOA, thrice per day; and the 38 patients in the control group receiving Western tertiary medicinal treatment. Gastroscopic picture and helicobacter pylori (HP) infection (by quick urease and Warthin-Starry stain) of the gastro-membrane, expressions of PS2 and PAF (by immunohistochemical assay and Western blotting) as well as the contents of aminohexose and phospholipid (by Neuhaus method) in the gastric membrane of all patients were detected before treatment and 4 weeks after treatment. The clinical efficacy in the two groups was compared. Results: The total effective rate in the treated group was 88.1%, which was significantly higher than that in the control group (78.9%, P