In recent years, some researches [95] found that diabetic patients have more Firmicutes and less Bacteroidetes than lean control; the change of gut microbiota caused activation of a network of inflammatory signal pathways via the Lipopolysaccharides (LPS) and CD14/toll-like receptor-4 (TLR4-) dependent pathway, which made the body in a state of low-grade inflammation; ultimately, T2DM came into being [96, 97]. RC was demonstrated to treat T2DM possibly via modulating the composition of gut microbiota (enrichment of beneficial microbiota and inhibition of harmful microbiota) [98]. Here, TLR4 is linked to type 2 diabetes mellitus.