marijuana, even infrequently, can cause burning and stinging of the mouth and throat, and cause heavy coughing as well as impairs the body's immune system from fighting disease.
and in a long run/ chronic smoker it can lead to cancer same as smokers.
is a kind of infection and the impaired immune system may help bacterias/ viruses to cause diseases with ease.
So to answer marijuana is harmful and will always remain same which ever way you take it, still those substance plays with human brain and first every one feels that they are in control of world and drug but after a while the drugs controls the body/brain
ADVICE: PLEASE QUIT BEFORE ITS TO LATE .