When someone aspirates, a foreign object, such as food or water, enters the person's airway. This generally results in coughing or gagging in an attempt to clear the foreign object. Choking results if the object blocks the airway. If the object ends up in the lungs, it can cause pneumonia.
Aspiration usually results when a person is distracted, sleepy or has a medical problem that affects sensation or motor function. It occurs more frequently as people age. A stroke or throat surgery can also increase a person's risk of aspirating. Paying attention while eating or drinking is advised to avoid aspiration.