G-418 disulfate (Geneticin sulfate) is an aminoglycoside antibiotic that selectively inhibits eukaryotic protein synthesis by blocking peptide chain elongation.

Continuous administration of G418 at doses ranging from 40 to 80 mg/kg for three consecutive days is sufficient to eradicate all untransfected Brucella bacterium parasites in infected mice.

At concentrations ranging from 1 to 300 micrograms/ml, G418 inhibits a variety of prokaryotic and eukaryotic organisms. Typically, concentrations of 5 mg/L or lower are effective against bacteria and algae, while a concentration of 400 mg/L is used for the selection of mammalian cells, and a maintenance concentration for mammalian cells is set at 200 mg/L.