Basically, there are two kinds of cough: productive and non-productive. Productive cough: A productive cough, also known as chesty cough, it is typically associated with a viral upper respiratory tract infection (URI), such as the common cold. Infection causes the mucous membrane of the bronchial tubes to become inflamed and produce thick, sticky mucus, so that it is no longer removed by the normal action of the cilia and clogs up the airways. Coughing is a reflex that expels this sticky mucus, also called phlegm. Inflammation and accumulated mucus narrow the airways, restrict respiration, and can promote bacterial infection. Non-productive cough (Dry cough): A non-productive cough is dry, tickling and irritating - a repeated stimulus in the respiratory tract and usually without expectoration. This cough can for example be caused by cigarette smoke or dust. It can also have an allergic or neurotic origin or can be caused by other perhaps more severe diseases.