Acetylcysteine effervescent is a mucolytic to expel phlegm and mucous secretions. Acetylcysteine effervescent works to dissolve phlegm and mucous secretions in the respiratory system associated with allergies. Acetylcysteine works to reduce the viscosity of sputum, thus facilitating its expulsion from the bronchi. Acetylcysteine is considered an auxiliary treatment for respiratory infections.