A cough is a spastic upward motion designed to expel unwanted material from the pulmonary system. However, people can generally control their coughing so that it occurs at a relatively convenient moment.
Coughs are caused most often by the common cold. Adults have 2 to 4 colds a year on average, each lasting 2 to 3 weeks. Coughing marks the first few days, and then gradually drops off by 80%. Children have 6 to 8 colds a year. The market for cough remedies in the UK in 1986 was £47 million.