The best way to alleviate a persistent cough is to stay hydrated according to WebMD. Upper respiratory infections such as cold or flu cause a post nasal drip where mucous trickles down the back of the throat and can cause coughing. Drinking water helps to thin the mucous and therefore reduce coughing.
In addition to thinning the mucous, drinking plenty of water can also alleviate dryness of the nasal passageways and mucous membranes, another common cause of coughing that results from seasonal changes or climate, explains WebMD. A popular treatment for coughs are throat lozenges with menthol that numb the back of the throat, and therefore reduce the coughing reflex. Drinking hot beverages sweetened with honey can also soothe the throat and reduce the impulse to cough.
A hot shower with a lot of steam can loosen the mucous secretions in the nose, which can be helpful for colds and seasonal allergies, states WebMD. Another suggestion for those suffering with a persistent cough is to install a humidifier, which can add moisture to the air and alleviate dryness; however, the humidifier filter needs to be cleaned regularly or it can become a source of illness itself, sending fungus, mold or bacteria into the air.