Cough is a very common symptom, many reasons can lead to our throat discomfort, always cough, and cough without phlegm may be the following conditions. 1. Cold. Cold is more common in our daily life, which may be caused by catching cold or not paying attention during the change of season. Sometimes the cough has phlegm, sometimes it does not, but in general there is no need to worry too much, prescribe some symptomatic medicine to eat a few days, basically it will be fine. 2. Bronchitis. A dry cough without phlegm may also be caused by damage to the bronchial tubes and bronchitis. In this case, it is also necessary to see a doctor in a timely manner, and if necessary, to do the appropriate examination. 3. Allergies in the respiratory tract. This condition is not rare. Especially when you ask for a strange smell or dry cough when you encounter irritation. In this case, you need to go to the hospital for examination and then choose a treatment plan for the cause. 4. Medication-based cough. Some medications can cause coughing as a side effect of the medication. The most common drugs that cause coughing are blood pressure lowering drugs, such as ACEI-type antihypertensive drugs. In either case, it should be treated promptly, and if you feel that just taking medication is not working, you should go to the hospital to get checked out by a doctor and then take an effective solution.