Dysphagia is any problem in which the action of swallowing is either difficult to perform, painful, or swallowed material is disrupted somewhere in the passage from the mouth to the stomach. Dysphagia may be caused by an anatomical problem (e.g. cancer) or a neurological problem (e.g. after a stroke). Dysphagia may also occur as a result of impaired control of swallowing for other reasons (e.g. as a result of breathing difficulties, or when a patient is very frail).