Nigericin is an ionophore antibiotic isolated from Streptomyces hygroscopicus. It has been shown to suppress DNA synthesis in Ehrlich ascites carcinoma. Nigericin is insoluble in water, but soluble in methanol and chloroform.

Nigericin sodium disrupts membrane potential by acting as an antiporter of H+ and K+ ions by exchanging K+ for H+. This causes a rapid decrease in intracellular pH.