What is marijuana? It is a green, brown, or gray mixture of dried, shredded leaves, stems, seeds and flowers of the hemp plant (Cannabis sativa). It is classified as a psychedelic drug and contains 420 chemicals, many of which are carcinogenic (cancer causing).

What is the most active chemical? THC or delta-9-tetrahydrocannabinol is the leading chemical.

How is marijuana used? Most users smoke a joint. This is placing loose marijuana into rolling papers. Another method is mixing marijuana into foods or brewing into a tea. Some users replace tobacco in a cigar with marijuana. This is called a blunt. Another method is using a pipe to smoke the loose marijuana. One well-known type of water pipe is the bong.

What happens after a person smokes marijuana? Within a few minutes of inhaling marijuana smoke, the users will likely feel, along with intoxication, a dry mouth, rapid heartbeat, some loss of coordination and poor sense of balance, and slower reaction time. The blood vessels in the eye expand, so the user's eyes look red.

How long does marijuana stay in the user's body? THC is readily absorbed by fatty tissues in the body. THC can be detected by a urine test for days and up to one month after use.

What are the long-term effects of marijuana? Findings show that the regular use of marijuana or THC may play a role in cancer and problems in the respiratory and immune systems.

How does marijuana affect the brain? THC affects the nerve cells in the brain where memories are formed. Some other problems include distorted perception of sight, sound, time and touch; trouble with thinking and problem solving; loss of coordination; and paranoia and anxiety or panic attacks.

What is tolerance? Tolerance is the need to take more and more of the drug to feel the affect. Marijuana users can develop a tolerance.

Can marijuana be used as medicine? Marijuana is a Schedule I controlled substance. This means it has a high potential for abuse; has no currently accepted medical use in the United States; and has no safe level of use under medical supervision. In considering possible medical uses of marijuana, it is important to distinguish between whole marijuana and pure THC. THC, manufactured into a pill that is taken by mouth, not smoked, can be used for treating the nausea and vomiting that go along with certain cancer treatments and is available by prescription.