Abstract： Objective： To analyze the regulatory mechanism of Wentong Prescription on breast microecology in lactational mastitis. Methods：A total of 68 patients with lactational mastitis admitted to Hangzhou Linping Hospital of Integrated Traditional Chinese and Western Medicine from January 2022 to October 2023 were enrolled. A selfcontrolled before-and-after trial was conducted， and all patients were treated with Wentong Prescription. The therapeutic effects were evaluated， and the relative abundance and diversity of breast milk and fecal flora before and after treatment were detected to analyze the regulatory effect of Wentong Prescription on breast microecology in lactational mastitis. Results： After treatment， the levels of Bifidobacterium， Lactic Acid Bacteria， operational taxonomic units（ OTUs），Faith's phylogenetic diversity index，Shannon's index，and Chao1 index in breast milk were increased when compared with those before treatment （P＜0.05）， while the levels of Staphylococcus Aureus and Enterococci were decreased （P＜0.05）. After treatment，the levels of Bifidobacterium，Lactic Acid Bacteria，OTUs， Faith's phylogenetic diversity index，Shannon's index，and Chao1 index in feces of patients were also increased when compared with those before treatment （P＜0.05）， while the levels of Staphylococcus Aureus and Enterococci were decreased （P＜0.05）. Compared with non-cured patients，cured patients had higher levels of Bifidobacterium，Lactic Acid Bacteria，OTUs，Faith's phylogenetic diversity index，Shannon's index，and Chao1 index in breast milk （P＜ 0.05） and lower levels of Staphylococcus Aureus and Enterococci （P＜0.05）. After treatment， the levels of Bifidobacterium， Lactic Acid Bacteria， OTUs， Faith's phylogenetic diversity index， Shannon's index， and Chao1 index in feces of cured patients were higher than those of non-cured patients （P＜0.05）， while the levels of Staphylococcus Aureus and Enterococci were lower （P＜0.05）. There were positive correlations between Bifidobacterium，Lactic Acid Bacteria，Staphylococcus Aureus，Enterococci，OTUs，Faith's phylogenetic diversity index， Shannon's index， and Chaol index in both breast milk and feces （r=0.526， 0.514， 0.601， 0.417， 0.589， 0.601， 0.588， 0.572， respectively； all P＜0.05）. After treatment， the levels of Bifidobacterium， Lactic Acid Bacteria， OTUs， Faith's phylogenetic diversity index， Shannon's index， and Chao1 index in breast milk and feces were positively correlated with the cure rate，while the levels of Staphylococcus Aureus and Enterococci were negatively correlated with the cure rate （P＜0.05）. Conclusion： Wentong Prescription regulates microecological disorders in lactational mastitis， increasing the levels of Bifidobacterium and Lactic Acid Bacteria while decreasing the levels of Staphylococcus Aureus and Enterococci. Furthermore， the microecological status of patients is correlated with the therapeutic effect of Wentong Prescription.