Sodium–glucose cotransporter 2 (SGLT2) inhibitors are a novel class of oral antihyperglycemic agents developed in recent years. They could block most glucose reabsorption in renal proximal tubules, thereby exerting glucose lowering effects through glycosuric ways. The renal and cardiovascular protection effects of SGLT2 inhibitors have also been demonstrated both in preclinical studies and clinical trials. However, SGLT2 inhibitors alone could induce an increase in endogenous/hepatic glucose production as well as in fasting plasma glucose levels; a sharp decrease of blood glucose concentration induced by SGLT2 inhibitors could also promote the secretion of counter-regulatory hormones such as glucagon, which has been reported to be associated with the occurrence of glycemic ketoacidosis. Therefore, coadministration of SGLT2 inhibitors and other antihyperglycemic agents should be considered when the therapeutic effect of SGLT2 inhibitors alone was unsatisfactory.