17 producing) cells [6]. SFB can promote IL-17-dependent immunity and autoimmune responses [7]. Wen L et al. [8] also demonstrated that NOD mice lacking the myeloid differentiation factor 88 (MyD88) protein, an adapter that recognizes microbial-stimulated innate immune receptors, did not develop type 1 diabetes. These studies suggest that changes in the gut microbiota are closely related to type 1 diabetes.Changes in the intestinal environment can affect microbiota, thus affecting the occurrence of type 1 diabetes. The diet is a direct factor that influences both the microbiota and a variety of other risk factors (Figure 1). For example, a gluten-free (GLF) diet has been shown to have antidiabetic effects in mice, possibly by altering the immune function and the composition of the gut microbiota, which is considered to be an immune-related environmental factor Abstract: Diabetes are a group of metabolic disorders characterized by persistent hyperglycemia that is a major public health problem. Middle-aged and elderly people are at the highest risk of type 2 diabetes, but younger cases are now being diagnosed with greater frequency. Numerous clinical studies have reported that the behavior of the intestinal microbiota may affect the development of metabolic disorders in humans, including obesity and diabetes. This review describes the relationship between the gut microbiota and diabetes, and discusses the possible mechanisms underlying their involvement in the development of type 1 diabetes, obesity, and type 2 diabetes. By better understanding the intestinal microbiota, it may become possible to treat diabetes and obesity by manipulating the gut microbes through probiotics and dietary changes, fecal microbiota transplantation, or surgical approaches.