Wikipedia article of the day: Cough:

A cough is usually initiated to clear a buildup of phlegm in the trachea; air may move through this passage at up to 480 km/h (300 mph) during a contraction.

Awesome:

A recent study indicates that, because of the presence of theobromine in chocolate, 50 grams of dark chocolate may be an effective treatment for a persistent cough.