Abstract
Polyene antibiotics are useful tools for studying the role of sterols in biological membranes. The interaction of polyene antibiotics with membrane‐bound sterols in artificial membrane systems, prokaryotic and eukaryotic cells, and lipid‐containing viruses is reviewed. The pentaene macrolide, filipin, is shown to serve as a probe of phosphatidylcholine‐sterol interaction and of the localization of cholesterol in the membrane of mycoplasmas.