From the ever-busy Department of Research into the Seemingly Obvious comes this: marijuana smoking can lead to coughing, wheezing and (yuck) phlegm.
Actually, I should give the researchers a bit of a break. It turns out that there's little understanding on what marijuana smoking actually does to the lungs, or to "pulmonary cliincical outcomes" as one study author put it.
The researchers looked at 14 studies of people who smoked pot for long periods. They did find a study that uncovered higher rates of coughing, wheezing and phlegm, none of which sound very healthy. On the other hand, most of the studies found that pot seemed to widen airways, at least temporarily.
Caveats:
Marijuana linked to respiratory complications [MedPage Today]