Coughing is how your body clears your lungs and airways. Coughing can also be a response to something that irritates your throat or airways. Sudden cough in babies or young children may mean they swallowed something that went into their windpipe. Usually, a cough is not harmful and will go away by itself. But sometimes it's a sign of an illness that needs treatment. Rarely, coughing warns of a dangerous problem that requires medical help right away.