Tyloxapol is a nonionic liquid polymer of the alkyl aryl polyether alcohol type that is used as a surfactant to aid liquefaction and removal of mucopurulent (containing mucus and pus) bronchopulmonary secretions. Tyloxapol is also used as a detergent, dispersing agent, encapsulating agent and a hydroxy radical scavenger. Tyloxapol has been used as a mucolytic agent for over 50 years and has proven to be well tolerated during this time. Tyloxapol influences the respiratory system by the following four different action mechanisms: secretolytic action, reduction of surface tension, dissolution of coatings and down-regulation of inflammation. Several studies have shown that small quantities of Tyloxapol applied as an aerosol liquefy sputum. The viscosity of sputum is reduced by 10% to 20% according to rotational viscosimetry measurements. Tyloxapol also penetrates the mucous wall and dissolves viscous and dried secretions, thus enabling increased ciliary activity in the respiratory tract. Although the mechanism of Tyloxapol has been well described, and there is a long-standing basis for its clinical usefulness, there are almost no randomized, double-blind, placebo-controlled trials available that demonstrate the superiority of Tyloxapol vs. saline. Side-effects in the form of hypersensitivity reactions have only occurred very rarely.