As a non-ionic surfactant, it is primarily used as an emulsifier for oil-in-water emulsions or creams, assisting in the dissolution of volatile oils and other oily substances, and functioning as a wetting agent in sulfur lotions. Its aqueous solution may become cloudy upon heating but returns to clarity upon cooling. Identification methods include a reaction with ammonium cobalt thiocyanate solution, resulting in a blue layer^[1]. Experimental studies have shown that polysorbate-80-modified poly(butyl cyanoacrylate) nanoparticles can assist drugs such as methotrexate in crossing the blood-brain barrier, thereby increasing drug concentrations in the brain^[2-3]. This substance has hemolytic properties, with Tween-80 exhibiting the weakest hemolytic effect among them.