Natamycin is a polyene amphoteric macrolide antibiotic with antifungal properties. Natamycin exerts its antifungal effects by binding to sterols in the fungal cell membrane thereby increasing membrane permeability. This leads to a leakage and loss of essential cellular constituents. Following ocular application, natamycin is retained in the conjunctival fornices and attains effective concentrations within the corneal stroma where it exerts its effect.