Cannabis, also known as marijuana, pot, hash, weed, grass and herb among many other names, refers to any number of preparations of the Cannabis plant intended for use as a mood-altering substance or for medicinal purposes. The word marijuana comes from the Mexican Spanish word, marihuana. According to the United Nations, marijuana "is the most widely used illicit substance in the world", despite it's legalization or quasi-legalization in a number of states and countries.

Marijuana is a mood-altering drug used throughout the United States and around the world.  Produced from the cannabis plant, marijuana is most commonly smoked through a pipe or cigarette (joint), but can also be eaten in the form of baked goods, lozenges, and drinks. Although marijuana is federally banned in the United States, some states have legalized medicinal use through prescription for ailments ranging from insomnia to cancer.  To date, marijuana is the most commonly used illicit drug in the US with users ranging in age, geography, income bracket, ethnicity, and religion.

New research indicates that teens are smoking pot more than they are smoking cigarettes.  The results of the research conducted by the Monitoring the Future Survey offer a mixed bag of implications, as while cigarette smoking is extremely harmful to a person’s health, marijuana is not without its share of negative health effects - including many that are similar to those produced by tobacco.

Marijuana is the most commonly used illicit drug in the nation.  With the low stigma marijuana use carries, it is freely accepted by a large percentage of the public, and not generally considered to be a dangerous drug, especially in comparison to other illicit drugs like heroin, cocaine, crack, and methamphetamine.  The fact is that marijuana can be extremely dangerous and destructive, and its use can have very harmful effects on a users brain and body.

According to the National Institute on Drug Abuse, Marijuana is the most commonly used illegal drug in the U.S. In 2009, 28.5 million Americans age 12 and older had abused marijuana at least once in the year prior to being surveyed.  In recent years, many states in the US have legalized medicinal marijuana prescribed by a doctor, and essentially decriminalized possession of small amounts of recreational marijuana with penalties of civil tickets and small fines.  Although it is not typically considered to be a dangerous and addictive drug in comparison to other illicit drugs, marijuana can have devastating effects on chronic users and can severely impair motor skills, reaction time, and judgment.