A cough is a sudden, forceful action that helps clear the airways of irritants, mucus, or foreign particles. It can be caused by various factors, such as a cold, allergies, or even smoke. When you cough, your body is trying to protect itself by expelling anything that might be causing discomfort or blocking your breathing. There are different types of coughs, including dry coughs and productive coughs. A dry cough doesn't produce mucus, while a productive cough brings up phlegm. Understanding the type of cough can help determine if you need to see a doctor or if it's just a minor issue that will pass.