Alison and Kendall have described my two most reliable "cures". In the first case, if you have enough hot whiskeies, you won't really care whether you get better or not. In the seconf case, a Nobel laureate can't be wrong, right?
There is, however, another remedy for severe congestion and "croup". It's a folk remedy that actually has a sound technical basis. Onions contain a variety of sulpher compounds, some of which are of medicinal value. Take a three pound bag of onions, slice coarsely, cover with water, put a lid on the pot, and bring to a boil. Remove from heat. Remove the lid from the pot, put a towel over your head and the pot, and breathe the vapors. Be careful not to get too close to the pot. The "steam" tends to help clear the sinuses, and the vapors seem to have a virucidal character. The "stew" remains potent for three or four days, but I've never needed it more than 48 hours. Just reheat it as needed. It's a lot less expensive that any other remedy, and a lot more effective than most