If you continue smoking pot during that period, it will accumulate in your brain cells. This can result in long and short tem memory loss, reduction of motivation, and impairment of even normal learning functions. Marijuana smoke contains more tar, carbon monoxide and known cancer-causing agents than tobacco. Marijuana is especially harmful to the lungs because users often inhale the unfiltered smoke deeply and hold it in their lungs as long as possible. Since the smoke is in contact with lung tissue for long periods of time, the lungs become more irritated and damaged than when smoking tobacco.
Scientists know that tobacco causes lungs cancer.
One joint of pot deposits 11 times the amount of tar and 5 times as much carbon monoxide as a cigarette does. Many pot smokers also smoke tobacco. That is double trouble for the lungs. The body protects itself against disease through its immune system. This means that marijuana use may increase a person's susceptibility to bacterial and viral infections such as colds and flu.