"The cysteine derivative N-acetyl cysteine (NAC) is often used as a cough medicine as it breaks up the disulfide bonds in the mucus and thus liquefies it, making it easier to cough up. NAC is also used as a dietary supplement as already indicated above."
In addition you could also buy some Tea Tree oil(health food store) and put a drop of undiluted oil just inside both of your nostrils. Tea Tree oil is anti most things, especially candida which goes hand in hand with a parasite infection. The aroma will reach your lungs. Don't do this too often though, in case it irritates your lungs.