Cetylpyridinium chloride is a cationic quaternary ammonium compound used in some types of mouthwashes, toothpastes, lozenges, throat sprays, breath sprays, and nasal sprays. It is an antiseptic that kills bacteria and other microorganisms.Cetylpyridinium chloride (CPC) is a quaternary ammonium salt antiseptic that is used in many over-the-counter personal-care products: mouthwashes, toothpastes, lozenges, and breath and nasal sprays, to name a few. It is also used in topical anti-infective products and as a pharmaceutical preservative.