Wild cherry bark is a time tested remedy for coughs - with supportive ingredients, of course. In my youth there were many cough syrup formulas with the cherry bark base.
Then along came dextromethorphan, which works quite well for two or three days, then back to the start line. The other effective remedy is codeine, for those who have serious need or like opioids! (Watch out for constipation! :^} )
One time I had a bad cough that would NOT go away, until I could tell it was affecting my heart, and the upper middle of my chest was swelling up. I did not have this cough syrup then, and got an Rx for the codeine cough syrup. Worked like a charm, except for the affect on the innards...
Wild cherry bark, in case anyone is not familiar with it, does NOT taste sweet or like cherries; it is quite bitter like many barks. My cough syrup tastes pretty good though. Honey preserves it plus soothes the throat and even helps deliver the therapeutic effects. And helps with “patient compliance”.