although not as fun, theobromine is also one of the key ingredients in tea -- it is a stimulant, and as a result, it increases blood flow, so the muscles in the lungs and throat are less sluggish and therefore better able to rid themselves of natural fluid, thereby requiring less need for coughing to achieve the same effect.
I also hear that cinnamon works wonders for coughs....
Thanks for the info. It's good to know.