What is a wet cough? A wet cough is a common symptom of respiratory infection, allergies, and heart conditions. The medical term for a wet cough is productive cough. A wet cough results from the presence of mucus or other fluid within the upper or lower respiratory tract. It may occur in conditions affecting one or both lungs, the bronchi, the larynx, or the pharynx. It may also be associated with more generalized conditions, such as a cold, hay fever, or the flu. Specific causes of a wet cough include infection and inflammation of the lungs (pneumonia) and bronchi (bronchitis). Other specific causes include chronic obstructive pulmonary disease (COPD), bronchiectasis (destruction and widening of the large airways), cystic fibrosis, and tuberculosis. Cancer of the lung is a common cause of a wet cough that may bring up bloody sputum (hemoptysis). Allergies involving the lungs (asthma) can also cause a wet cough. Heart conditions can lead to a wet cough; serious causes include fluid buildup in the lungs due to an acute episode of congestive heart failure. Elevation of the head during rest may improve wet cough symptoms. In some cases, a wet cough may be a sign of a serious or-life threatening condition. Seek immediate medical care (call 911) if you, or someone you are with, have serious symptoms, such as severe difficulty breathing and sharp chest pain, which may be accompanied by high fever (higher than 101 degrees Fahrenheit), pale or blue lips, change in level of consciousness or alertness, or rapid heart rate. Seek prompt medical care if you are being treated for a wet cough but mild symptoms recur or are persistent.