Benzalkonium chloride (BAC) disinfects and preserves, it is in most multi-dose aqueous nasal, eye, and ear products. Preservative for eye drops, at 0.01-0.02%, it has been the most common eye drop preservative since the 1950s, its multidose container-effective bactericide and fungicide and reduces organism growth. Many drugs contain preservatives, ophthalmology's main preservative is BAC . More than 200 EU-approved nasal and 10 inhaled medications contain BAC as a preservative. Some BAC medicines can be used on the skin, oral cavity, oral mucosa, rectal, vaginal, and parenteral routes .