To explore mechanism of intestinal flora dysregulation promoting constipation, 
60 specific pathogen-free (SPF) mice were used as research objects and 
were treated with constipation population fecal fluid gavage and distilled water 
gavage. Then, relationship between intestinal dysregulation and constipation in 
mice with biofilm-mediated intestinal flora was investigated in vitro. The 
results showed that recombinant serotonin transporter (SERT) messenger 
ribonucleic acid (mRNA) level of the constipation population fecal fluid gavage 
group and the relative expression level of SERT mRNA were 1.61 ± 0.08 and 1.49 ± 
0.06, which were higher markedly than those of distilled water group (P < 
0.05). The level of 5-hydroxytryptamine (5-HT) in colonic tissue of the 
constipation population fecal fluid gavage group was 145.36 ± 14.12 ng/mL, and 
the expression level of 5-HT on the surface of epithelial cells of 
biofilm-positive colonic tissue was 20.11 ± 2.03, which were significantly lower 
than those of the distilled water group, with statistical significance (P < 
0.05). Besides, the microbial sequencing of fecal flora indicated that The Akk 
and bacteroidetes ofconstipation population fecal fluid gavage group were higher 
hugely than those of distilled water group (P < 0.05).In conclusion, after the 
occurrence of constipation, the diversity of intestinal microflora decreased, 
and the probiotics reduced. Iintestinal microflora dysregulation would lead to 
increase of SERT expression level in defecation function and intestinal motility 
in mice, and the decrease of 5-HT, thereby changing the intestinal movement 
resulting in mucosal protective barrier damage,thereby causing changes in 
intestinal movement and the destruction of the intestinal mucosal protective 
barrier, which eventually resulted in constipation. The occurrence of 
constipation could be improved by regulating balance of intestinal flora, 
increasing the diversity of flora, and reducing the genus of opportunistic 
pathogens.