Whether you buy it yourself, or someone hands you the joint, the marijuana you're smoking may not be pure. It may be laced with PCP, pesticides, LSD, crack, or even embalming fluid!

It’s not just what’s in the blunt or bong that’s a problem. Getting high is risky in a lot of ways — and not just medically. Intoxication compromises mental functioning in the short term by affecting memory and learning. Motor coordination and perception of sights, sounds, time, and touch are affected, which can cause car accidents and (let’s face it) sexual problems. Lowered inhibitions can result in STDs and relationship problems. And you can also get a nasty chronic cough and mess up your respiratory and immune systems.

Put this in your pipe and smoke it.

Just because it's natural doesn't mean it's harmless. After all, heroin comes from poppies and cocaine comes from coca leaves. Marijuana is not just a harmless weed.

True, the laws in some states permit the use of marijuana for medical purposes. That is because THC — the active ingredient — is so powerful that it can help treat the symptoms of glaucoma and reduce nausea in patients with HIV/AIDS or cancer. However, under U.S. law, it is a Schedule I Controlled Substance that is not widely accepted for medical use.

When doctors prescribe "Marinol" (the pill form of THC), they have decided that the benefits of THC outweigh the risks in these cases. What kind of risks? How about gynomastia (“man boobs”), weight gain, sterility, decreased aerobic functioning, and panic or anxiety attacks? Or a lack of motivation to do everyday tasks, like writing papers and studying for exams.

Stronger than Ever

Marijuana is even riskier today because so much of the marijuana on the market is grown indoors and bred for specific qualities, like potency. This means that most of the marijuana that students smoke today is much stronger than it was for their parents’ generation. The average THC level rose from less than 1% in the late 1970s to more than 7% in 2001.