About Carbocysteine Mucoactive drug, : local anti-infective agents, expectorants. Mechanism of Action of Carbocysteine Carbocysteine is a mucolytic which liquefies the viscid sputum. It acts on the metabolism of mucus producing cells. It induces the production of mucus with increased sialomucin content. Sialomucin influences the rheological properties of mucus and also inhibits kinins and prevents bronchial inflammation and bronchospasm. It normalizes mucus viscosity and reduces goblet cell hyperplasia.