Abstract: Objective: To investigate the effect of Heyndrickxia coagulans BC07 on loperamide hydrochloride-induced constipation in mice.Methods: Thirty mice were randomly divided into three groups: the normal control group (NC), the model group (MC), and the BC07 group, with 10 mice in each group. The NC and MC groups were intragastrically administered normal saline, while the BC07 group was intragastrically given Heyndrickxia coagulans BC07 bacterial solution for 14 days. From the 15th to the 17th day, loperamide hydrochloride was used to establish the constipation model. The time to the first black feces and intestinal transit in mice were observed. Feces, serum, cecum, and colon samples of mice were collected.Results: The intake of Heyndrickxia coagulans BC07 could significantly increase the feces water content in constipated mice (P<0.05), shorten the time to the first black feces in mice (P<0.05), and promote the propulsion rate of the small intestine. Meanwhile, it could effectively regulate the concentrations of motilin (MTL), vasoactive intestinal peptide (VIP), substance P (SP), and somatostatin (SS) in constipated mice. It also reduced the contents of pro - inflammatory cytokines IL-6 and TNF - α in the mouse serum and increased the level of the anti - inflammatory factor IL-10. In addition, after the supplementation of Heyndrickxia coagulans BC07, the structure of the intestinal microbiota in constipated mice could be effectively regulated, increasing the relative abundance of beneficial microbiota in the mouse intestine and significantly decreasing the relative abundance of harmful microflora (P<0.05).Conclusion: Heyndrickxia coagulans BC07 has the effect of increasing fecal water content and alleviating defecation difficulties. It is speculated that it may relieve constipation by regulating gastrointestinal peptide transmitters, improving the structure of the intestinal microbiota, and promoting intestinal peristalsis.