guaifenesin /gwī′əfen″əsin/ , glyceryl guaiacolate, a white to slightly gray powder with a bitter taste and faint odor, widely used as an expectorant. Guaifenesin increases the flow of fluid in the respiratory tract, reducing the viscosity of bronchial and tracheal secretions and facilitating their removal by the cough reflex and ciliary action. It may increase the risk of hemorrhage in patients taking heparin.
