A cough is your body's way of clearing irritants from your throat or lungs. Sometimes, it sticks around longer than it should. If you have been coughing for more than eight weeks, it is considered chronic. This can be frustrating and tiring. It often interrupts your sleep and makes it hard to get through your day. Understanding why this happens is the first step toward feeling better. Finding the Cause Many things can lead to a persistent cough. Allergies and asthma are common triggers. Post-nasal drip, where mucus runs down the back of your throat, often causes a tickle that makes you cough. Acid reflux is another frequent culprit. Sometimes, stomach acid comes up and irritates the throat without you even feeling the burn. In some cases, the cause might be a medicine you take for blood pressure. It is also possible that a previous infection left your airways sensitive. Because there are so many possibilities, a doctor needs to look at your full health history. What to Expe...