Food aspiration is a medical emergency in which food enters the body's airway or lungs. The body's adverse reaction to food aspiration is choking, when throat contractions attempt to expel the aspirating food from the airway. Liquid aspiration is very similar to food aspiration, but differs in that unlike food, liquid enters the respiratory system. While many cases of food aspiration are naturally resolved by the body's defenses and are not fatal, aspirated food or chronic inhalation can lead to debilitating respiratory disease or damage to the body from lack of oxygen or infection.

In the body, the upper respiratory tract, consisting of the sinus cavities, pharynx and larynx, lies in close proximity to the upper digestive tract, which consists of the mouth, tongue and throat. These two tracts share one tube, called the esophagus. The esophagus leads to two organs: the stomach and the lungs. A small muscular flap called the epiglottis controls the direction of either air or food, and channels the contents to the proper organ.

Food aspiration may occur for a number of reasons. The epiglottis may not function properly, therefore allowing food contents to spill into the esophagus and lungs. Choking may occur when a person simultaneously talks and eats, causing the tongue to accidentally push food rather than air into the airway. Other causes may include cancer of the throat or other organs, lack of muscle control, trauma, unconsciousness, the use of sedatives, or a multitude of others.

The body reacts strongly to aspirated food, autonomously producing throat convulsions, coughing fits, drooling and vomiting. Muscle contractions may force out small sections of food from the upper respiratory tract, but food that enters the lungs is a medical emergency. Infection may not become immediately evident. Common symptoms of infection from aspirated food include wheezing, foul-smelling or discolored sputum, chest pain, fever, and cyanosis — a bluish color of the skin from lack of oxygen. Severe lung inflammation may develop into aspiration pneumonia or a lung abscess, requiring hospitalization and a regimen of antibiotics.

To prevent food aspiration, a person should take small bites of food and eat slowly. Sedatives, muscle relaxants and other drugs should be avoided when possible, as these medications slow the esophageal muscular contractions. Hospitalized patients, with whom food aspiration is a common concern, should sit up as much as possible.