The spicy kick of mustard seed is one sign that this plant may help cut through the thick congestion that accompanies so many bouts of bronchitis. Throughout history, mustard poultices and "plasters" have been used to kickstart the immune system, reduce pain, and of course, serve as a potent expectorant to help keep mucus flowing more freely. Frantic doctors applied mustard plasters to President Abraham Lincoln the day he was shot and killed by an assassin [sources: Amarillo Globe-News, Canavan].
The warmth of an old-fashioned mustard plaster relieves symptoms of many respiratory ailments, including bronchitis. Take 1 tablespoon dry mustard and mix with 4 tablespoons flour. Stir in enough warm water to make a runny paste. Oil the chest with vegetable shortening or olive oil, then spread the mustard mix on a piece of cloth -- muslin, gauze, a kitchen washcloth -- and cover with an identical piece.
Apply to the chest. Keep in place until cool (about 10-20 minutes), but check every few minutes to make sure it doesn't burn the skin. Remove the plaster if it causes discomfort, because it can create serious skin pain and even blisters if you leave a potent blend in place too long [source: Homesteading Family].