Smoking of any kind has shown to lead to lung cancer and other lung based problems. Which makes sense, our bodies were not designed to be filled with smoke.
But weed doesn't have all the chemicals and stuff that cigarettes have.
Tobacco has natural amounts of tar in it.
Marijuana does not.
Tar is what really causes the cancer in smoking.
Seriously, I'm not stupid. I wouldn't smoke something if I thought that it was dangerous in any way, shape or form.
(dangerous meaning it can kill you if you even have a small bit of it)
Most marijuana users don't take dangerous drugs like cocaine and heroin. Those two are very dangerous. I wouldn't even consider taking them.
Acid and shrooms are like weed; improbable to OD on. Just, like weed, can have a negative affect on your brain if your brain isn't fully developed or past a certain stage of developement.
Marijuana is more or less 100% safe after the age of 16, and in almost all users, completely safe after 15. When you're 14, I wouldn't risk it.
Shrooms and acid are things you don't take until you're at the very, very least 17. I'll probably take my first few shrooms when I'm 17. Acid/LSD when I'm 20 or more. Those two drugs cannot kill you, or at least, unless you take a ridiculously impossible amount of it.