Gut microflora that has been present in our bodies since infancy are known to influence health, metabolism, and disease. Diabetes is a developing epidemic, and treatment that cures diabetes has yet to be discovered. Probiotics are living bacteria that may colonize the human gastrointestinal system and help to maintain a healthy microbiome and help normalize disrupted metabolism in diabetic patients. Lipopolysaccharides, trimethylamine, and imidazole propionate seem to hinder insulin signaling, whereas secondary bile acids, short-chain fatty acids (SCFAs), and tryptophan metabolites seem to enhance it. This chapter emphasizes the relationship between gut microflora and impaired glucose metabolism. This chapter also covers the mechanisms through which probiotics alleviate diabetes by addressing the gut microflora from the perspectives of amino acid metabolism, intestinal permeability, immunological responses, oxidative stress, and SCFAs.