A cross sectional descriptive 2-phase study was carried out on 800 documents from patients who were prescribed proton pump inhibitors for treatment gastritis in internal medicin department at An Giang central general hospital, to assess the use of proton pump inhibitors. The 1 st phase: The retrospective study was carried out on 400 patients from may 2016 to august 2016. The 2 st phase: The prospective study was carried out on 400 patients from december 2016 to april 2017. The rate of using rational PPI use was 72,5% for 1 st phase and 91,2% in 2st phase. Based on the results of this study, a guideline for rational prescribing of PPIs needs to be implemented in order to reduce the improper use of these drugs.