Pooling occurs when a person’s swallow does not successfully send the entire mass of food or liquid into the esophagus, so that some or all of the material remains in the hypopharynx. In such cases, the material commonly pools in the vallecula and pyriform sinuses. It can also cling to the base of the tongue or the pharyngeal walls. Pooling is often caused by presbyphagia, and its occurrence may put a patient at risk of aspiration.