I came across a recent post on earthclinic. I've had a chronic cough for years. finally went to pulmonologist, who diagnosed adult onset asthma, and wanted to put me on Advair. Googled advair and it scared me. Google herbal remedies and came up with "Mullein". Bought a bottle. 30-35 drops in a little water a couple times a day. THE VERY FIRST NIGHT, i took it around 7 pm for the first time, and unbelieveably I was cough-free that night for the first time in i dont know how long. Been on it 3 weeks and its still working (as long as I take it :) ). One site said it may not work for everyone (like everything, I suppose) but it worked for me. Common herb, googleit and try it. Good luck.
I have used mullein extract in the past and it has stopped my wheezing almost instantly.