4. Marijuana suppresses the immune system

Like the studies claiming to show damage to
the reproductive system, this myth is based on studies where
animals were given extremely high -- in many cases,
near-lethal -- doses of cannabinoids. These results have never
been duplicated in human beings. Interestingly, two studies done in
1978 and one done in 1988 showed that hashish and marijuana may
have actually stimulated the immune system in the people studied.