Marijuana (also spelled marihuana) is the common name given to any drug preparation comprising the leaves and the flowering tops of the Indian hemp plant, Cannabis sativa. There are various forms of this drug known under different names throughout different countries, depending on the method of preparation, which affects the potency of the drug. Ganja, from India, is three to four times more potent than marijuana, while hashish is five to eight times more potent. Other names for it are kif from Morocco and dagga from South Africa, while it has also acquired a variety of slang names from the Western culture such as grass, pot, tea, reefer, weed, and Mary Jane.
The leaves and flowers of the plant are dried and crushed or chopped into small pieces. It has been smoked, eaten in cakes, drunk in beverages, or, rarely, injected intravenously. In Western cultures marijuana is prepared most often as a tobacco-like mixture that is smoked in a pipe or rolled into a cigarette.
The smoke from marijuana is harsh although it has a sweetish odor, which smells like burnt rope or dried grasses.
The primary psychoactive component of this drug is delta-9-tetrahydrocannabinol, a compound--C21H30O2, commonly known as THC. It has a high lipid solubility allowing it to accumulate in fatty tissues, which are then detected even if weeks or months have passed since its use. THC also disrupts the nerve cells in the parts of the brain where memories are formed and may have long-term memory loss for long time users. Other abundant cannabinoids in marijuana are cannabidiol and cannabinol. These cannabinol derivatives are thought to be intoxicating.
Controversy surrounds the medical use of marijuana, with proponents saying it is useful for treating pain and the nausea and vomiting that are side effects of cancer chemotherapy...