Fig. 7

a The relative abundance of Clostridium was significantly increased. b The abundance of Lachnospiraceae was not significantly increased. c The abundance of Peptostreptococcaceae was not significantly increased. dClostridium was positively correlated with secondary bile acids (Spearman’s correlation, p < 0.01, r = 0.609, n = 29). e The abundance of Eubacterium was significantly decreased in the gallstone group. f At the species level, the relative abundance of species. gEubacterium was positively correlated with coprostanol (Spearman’s correlation, p < 0.01, r = 0.663, n = 29). h A significant increase in intestinal free bile acids was observed in the gallstone group. i The results showed a significant increase in secondary bile acids in the gallstone group. j This study showed that coprostanol was significantly higher in the gallstone group than in the control group. k The Lactobacillus abundance was positively correlated with the free bile acid concentration (Spearman’s correlation, p < 0.05, r = 0.457, n = 29). All data are expressed as the mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001, ns > 0.05, Statistically significant differences (p value < 0.05) between the two groups were determined by Mann-Whitney U test in A, B, C, E, F, and H. Statistically significant differences (p value < 0.05) between groups were determined by Student’s t test in Fig. 7 I and J