An acute cough is a short-lived cough that usually lasts less than three weeks and is often caused by common respiratory infections such as colds, flu or bronchitis. It can also be caused by triggers such as smoke or allergens. This type of cough usually goes away on its own as the underlying cause, such as an infection, is treated or the irritant eliminated. In this situation, an herbal cough and cold remedy can speed up the healing process and help.