ObjectiveTo observe the effect of Banxia Xiexintang （BXT）-containing intestinal absorption solution on the apoptosis of polymorphonuclear myeloid-derived suppressor cells （PMN-MDSCs） in gastric cancer microenvironment. MethodBXT-containing intestinal absorption solution was prepared， and gastric cancer cells and PMN-MDSCs were non-contact co-cultured in Transwell chamber to establish gastric cancer microenvironment. Cell counting kit-8 （CCK-8） assay was used to screen the optimal intervention concentration and time of 0-100% BXT-containing intestinal absorption solution prepared by 0.63 g·mL-1 reconstitution solution. Cells were classified into blank group， model group， oxaliplatin group （10 mg·L-1）， and BXT （26%， 18%， 10% BXT-containing intestinal absorption solution） group， and the apoptosis of PMN-MDSCs was detected by flow cytometry. The expression of apoptosis-related B-cell lymphoma 2 （Bcl-2）， Bcl-2-associated X protein （Bax）， and cysteine-aspartic acid protease-3 （Caspase-3） in PMN-MDSCs was detected by Western blot. ResultAfter treatment for 24 h and 48 h， the PMN-MDSCs-inhibiting rate was increased by 5%， 50%， 75%， and 100% BXT-containing intestinal absorption solution compared with that in the blank group （P<0.05， P<0.01）. At 72 h， the PMN-MDSCs-inhibiting rate by 50% BXT-containing intestinal absorption solution was lower than that at 48 h （P<0.01）， and the PMN-MDSCs-inhibiting rate by 5%， 75%， and 100% BXT-containing intestinal absorption solution showed no significant difference from that at 48 h. Moreover， the half-maximal inhibitory concentration （IC50） at 48 h was 18.40%. Thus， 18% BXT-containing intestinal absorption solution and 48 h were the optimal intervention concentration and time. The survival rate of PMN-MDSCs in model group was higher than that in the blank group （P<0.05）， and the apoptosis rate was lower than that in the blank group （P<0.05）. Compared with model group， BXT containing intestinal absorption solution lowered the survival rate and raised apoptosis rate of PMN-MDSCs （P<0.05）， particularly the 26% BXT-containing intestinal absorption solution （P<0.05）. The expression of Bax and Caspase-3 in PMN-MDSCs was lower in the model group than in the blank group （P<0.05）， and the expression of Bcl-2 was higher in the model group than in the blank group （P<0.05）. The expression of Caspase-3 in PMN-MDSCs increased （P<0.05） and the expression of Bcl-2 decreased （P<0.05） in oxaliplatin group and BXT group compared with those in the model group. The expression of Bax rose in oxaliplatin group and BXT group （10% BXT-containing intestinal absorption solution） （P<0.05）. ConclusionBXT can induce the apoptosis of PMN-MDSCs by regulating the expression of apoptosis-related proteins Bax， Caspase-3， and Bcl-2 in gastric cancer microenvironment.