When anyone in my home, (including guests)have a cough, I get out my largest pot fill it with water Add 1 tablespoon of Oregano and 1 tablespoon of Thyme, turn to a simmer once it comes to a boil. Have a person stand over the steam and breath deep, this will make them cough up anything in the lungs. Breath in the steam until coughing is eased. Leaving the pot on simmer, adding water and more of the herbs if needed. I find that at least two days is the time frame to illuminate a bad cough. This combination takes care of both viral and bacterial causing coughs. Can be used with other remedies. I put this in a crock pot on low in sick rooms if the aroma doesn't reach from the kitchen.
Sometimes I got rid of a bronchitis with raw garlic but a stubborn dry cough persists. I get rid of that by inhaling water with a simple steam inhaler 3 times a day for 5 - 10 minutes. The dry cough is gone within 4 - 5 days. God bless to all!