In short, our data show that the gut microbiota can be modulated by Li01 intervention in mice with loperamide-induced constipation by increasing the ratio of Firmicutes/Bacteroidetes and the abundance of genera Rikenellaceae_RC9. Li01 changes the 5-HT signaling, with increased expression of Tph1 and 5-HTR3 and 5-HTR4, leading to elevated levels of 5-HT in the colon and enhanced gut motility and fluid secretion. Here, TPH1 is linked to Constipation.