"Foreign" means "originating elsewhere" or "outside the body." Foreign bodies usually get stuck in the eyes, ears, nose, airways, and rectum of children and adults. Young children may intentionally put shiny objects into their mouths and stick things in their ears and up their noses. Adults may accidentally swallow a non-food object or inhale a foreign body that gets stuck in the throat. Airborne particles can get stuck in the eyes of anyone. Foreign bodies can be in hollow organs (like swallowed batteries) or in tissues (like bullets). They can be inert or irritating. If they irritate they will cause inflammation and scarring. They can bring infection with them or acquire it and protect it from the body's immune defenses. They can block passageways either by their size or by the scarring they cause. Some can be toxic.

Dust, dirt, sand, or other airborne material can...