Marijuana, also called “grass,” “pot,” or “weed,” is made from a plant called Can nabis saliva. Tetrahydrocannabinol, or THC, is the main chemical in marijuana. The more THC in a marijuana cigarette or joint, the greater the high.

At first a smoker may feel relaxed and silly. But later the user becomes sleepy.

Marijuana increases your pulse rate and makes your eyes bloodshot. Your mouth becomes dry. It affects your brain, making it hard to concentrate. It also affects your sense of timing and muscle movement, making it dangerous to drive.

Some users have panic attacks and become paranoid. Long-term use also makes a user lose interest in life. That leads to learning problems at school and makes it hard to keep a job.

Marijuana smoke contains even more cancer-causing chemicals than tobacco smoke. Smoking the two together is even more harmful to your body.

THC is stored in the fatty parts of body cells. Since one third of your brain contains these fatty cells, it takes a long time for THC to leave your body. The chemicals from a single joint can take a month to leave, even though the smoker felt the high for only a few hours.