My friend says marijuana does no harm to your body and uses excuses like its better than cigarettes ? what are some reasons he should not smoke

Not true : Marihuana can cause symptoms similar to schizophrenia, because often is laced many people end i. The er. My advise do not use it.

Tar, mood effects: Marijuana smoke has more "tar" than cigarettes, and therefore is at least as bad for the lungs. Smoke in general is unhealthy to inhale, can worsen asthma, bronchitis, etc. Marijuana can also make a person anxious or paranoid, worsen depression, or push a person into psychosis if they were already tending that way. All drugs have harms that must be weighed, nothing is completely harmless.

MJ less safe: As the other docs responded, mj is worse than tobacco. But it is bad for your brain from day one! it can lower your iq, impede your judgment, increase risk of serious auto accidents, and lead to schizophrenia in susceptible people. Mj does plenty of harm, and no good to your body.