I am 32 and relatively healthy. I have had a cough for a few weeks now. About once a day, usually in the evening I cough so hard that a lot of clear liquid comes up. If I spit it into a regular sized drinking glass, it is about 1/2 of an inch of thick clear liquid. the cough usually gets better shortly after that happens for a short time. I don t think I am vomiting as it can not long after I eat and there will be no food of bile in the liquid. Where is the liquid coming from and should I be concerned. I have no other symptoms other than the severe cough.