OBJECTIVE:Investigate the determination of gastric acid neutralization of concha margaritifera.METHODS:Using the method of acid-base neutralization and setting it in water bath at 37℃ for 1h.RESULTS:1g of concha margaritifera could neutralize 145.34mL of 0.1 mol?L 1 HCl solution.2g,bid almost neutralized body gastric acid secreted in a day.CONCLUTION:Concha margaritifera is an effective natural medicine in neutralizing gastric acid.