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The general outline of this therapy can be found here: Best natural cough treatment. This is the way how you can stop coughing for good. An additional factor to stop coughing naturally is to use Earthing for grounding the human body to get Earth's electrons to reduce inflammation.
If you have a productive cough, it is best not to take medication to suppress it. Suppressants stifle the cough reflex and help you stop coughing. Research on cough suppressants has shown that they do not work for many people. If you do choose to use a cough suppressant, they should generally only be used at night.