Cetylpyridinium chloride (CPC) is a quaternary ammonium surfactant having broad spectrum antimicrobial activity. The hexadecane chain of the CPC disorganizes lipid membrane and produces a complete rupture of the bacterial cell membrane. At low concentration of CPC, it leads to activation of intracellular latent ribonucleases of microbes to promote cell autolysis. At high concentration, CPC forms a vesicle-like structure in the bacterial cell surface and leads to leakage of cytoplasmic content. CPC can be estimated using several methods like HPLC, ion-pair extraction TLC, spectrophotometry, chemiluminescence, and spectrometry. It is a strong antimicrobial, anti plaque, deodorizer and bleeding control agent and is widely used in mouthwashes, tooth paste, sanitizers and disinfecting liquids. Keywords: Cetylpyridinium chloride, antimicrobial agent, deodorizer, anti plaque agent.