Aspiration pneumonia is a chest infection that is cause by regurgitated stomach contents (food or secretions) or swallowed food travelling down into the lungs. This causes quite a nasty focus of infection and requires specific antibiotics. The prognosis depends on the individual case but is worse than for common or garden pneurmonia.

It occurs when the normal protective mechanisms that prevent food/fluid going down into the lungs are impaired (cough reflex, normal swallow) which sometimes occurs with stroke.