expectoration

Expectoration is the formal name for the act of coughing up secretions from the chest and spitting them out. Where mucus is the substance and cough is the force, expectoration is the whole event of bringing that mucus up and out of the body through the mouth.

Mechanically it combines the cough reflex with the upward movement of mucus: a deep breath, a forceful expiratory burst that shears the mucus off the airway walls and drives it up, and finally clearing it from the mouth. Effective expectoration depends on having enough air flow, a strong cough, and mucus that is not too thick to move.

Clinically, doctors ask whether a cough is productive (with expectoration) or dry, and they note the amount, color, and character of what is brought up, since these point to different conditions. When natural expectoration is weak — after surgery, in neuromuscular disease, or with very tenacious secretions — physiotherapy, hydration, and mucus-thinning treatments are used to assist it.