Multidrug transporters, such as MFSD1, are membrane proteins that expel a wide spectrum of cytotoxic compounds from the cell and render cells resistant to multiple drugs. The Major Facilitator Superfamily (MFS) is a large and diverse group of secondary transporters that include uniporters, symporters, and antiporters. Members of this family are found in all living organisms and are highly represented in bacteria. MFS members are capable of transporting various substrates such as sugars, polyols, drugs, neurotransmitters, amino acids, peptides, and inorganic anions, although most members are substrate-specific. MFS have provided important insight into the mechanism underlying multidrug transport. MFSD1 is still poorly understood.