Before any teen decides to use marijuana, they should wait to see the kinds of cancer,resapiratory and imune system problems that occur after the use of the drug.

Cancer
It’s hard to know for sure whether marijuana use alone causes cancer, because many people who smoke marijuana also smoke cigarettes and use other drugs. But it is known that marijuana smoke contains some of the same, and sometimes even more, of the cancer-causing chemicals found in tobacco smoke. Studies show that someone who smokes five joints per day may be taking in as many cancer-causing chemicals as someone who smokes a full pack of cigarettes every day (15) .


Lungs and airways
People who smoke marijuana often develop the same kinds of breathing problems that cigarette smokers have: coughing and wheezing. They tend to have more chest colds than nonusers. They are also at greater risk of getting lung infections like pneumonia.


Immune system
Our immune system protects the body from many agents that cause disease. It is not certain whether marijuana damages the immune system of people, but both animal and human studies have shown that marijuana impairs the ability of T-cells in the lungs' immune systemm to fight off some infections.