The Organic Cation Transporter (OCT) family is a group of transmembrane proteins responsible for the transport of organic cations into and out of cells. The main family members include OCT1, OCT2, and OCT3, which consist of multiple transmembrane domains and are mainly located in the cell membrane of tissues such as the liver, kidneys, and nervous system. These transporters are involved in regulating the transport of drugs, endogenous metabolites, and neurotransmitters by promoting the transmembrane transport of organic cations, affecting cell function and survival. The expression of OCT family members is tissue- and cell-specific, and mutations or dysregulation of their genes are associated with various diseases, including drug metabolism disorders, kidney diseases, and neurological disorders.