Phosphorylcholine chloride (Phosphocholine chloride) is a zwitterionic small molecule that forms the hydrophilic head group of major eukaryotic membrane phospholipids and is also found on the surface of commensal or pathogenic bacteria associated with eukaryotes. It exhibits immunomodulatory properties and commonly used in biomaterial coatings to reduce protein adsorption, prevent unwanted cell adhesion, and improve implant biocompatibility.