What will happen if small amount …

When you swallow food, it passes from your mouth down into your throat (pharynx). From there, the food moves down through a long tube (the esophagus) and into your stomach. This journey is made possible by a series of actions from the muscles in these areas. Dysphagia happens when there is a disruption in the swallowing process as food and liquids pass through your mouth, throat, and esophagus. 

The pharynx is also part of the system that brings air into your lungs. When you breathe, air enters your mouth and moves into the pharynx. The air then goes down into your main airway (trachea) and into your lungs. A flap of tissue called the epiglottis sits over the top of the trachea. This flap blocks food and drink from going down into the trachea when you swallow. But in some cases, food or drink can enter the trachea causing aspiration. It may go down as you swallow. Or it may come back up from the stomach. A person with dysphagia is much more likely to aspirate.

Dysphagia is more common in older adults. Stroke is a very common cause of both dysphagia and aspiration. About half of people who have had a stroke also have dysphagia. About half of people with dysphagia have aspiration. About one-third of these people will need treatment for pneumonia at some point.