摘要Background : In China, Rhizoma atractylodis macrocephalae- Paeonia lactiflora Pall (Biazhu- Baishao, BZBS) is a classic herb pair used to treat intestinal stress syndrome, ulcerative colitis and other diseases. However, the mechanism of BZBS in the treatment of functional constipation (FC) has been little studied and remains unclear. In this study, a behavioral investigation, colon tissue morphology, enzyme- linked immunosorbent assay (Elisa) and intestinal microflora analysis have been used to illuminate the potential mechanism of the effects of BZBS on FC in a rat model.Methods : A FC rat model was constructed and BZBS was given as treatment. Observations and recordings were made of the fecal moisture content, the defecation time of the first black stool, and the rate of intestinal propulsion. Elisa was used to detect the expression levels of substance P (SP), vasoactive intestinal peptide (VIP), 5- hydroxytryptamine (5- HT) in the colon. To ascertain the composition of the microbial community, a high throughput 16S ribosomal RNA (16S rRNA) gene sequencing technique was employed. Results : Oral administration of BZBS significantly ameliorated several key excretion parameters, including the time to first black stool defecation, stool water content, and the propulsion rate in the small intestine in FC rats. It increased the expression of SP, VIP and 5- HT in the colon. 16S rRNA gene sequencing results showed that BZBS changed the microbial community structure, decreased the Bacteroidetes/Firmicutes ratio, increased the relative abundance of Blautia and Fusicatenibacter , and decreased the relative abundance of Ruminococcus and Roseburia . Conclusions : BZBS effectively alleviates FC and improves dysbacteriosis.