Marijuana is the common name for the hemp plant Cannabis sativa. Hemp grows in tropical as well as temperate climates. The dried ground leaves, flowers, and stems of the plant have a long history for their use as drugs. It has been cultivated in different regions of the world throughout centuries for its fiber to produce linen, rope, canvas, and oil. It has also been used as a medicine to relieve symptoms of illness and as a euphoric to induce states of intoxication or elation. Throughout its long history, parts of the plants have been smoked, eaten, chewed, or brewed for its pharmacological effects on human biochemistry.
There are over 400 chemicals in cannabis. By the mid-1960s the main psychoactive chemical was identified as tetrahydrocannabinol, commonly referred to as THC. Since then, other psychoactive compounds have been isolated from the plant and are being studied for their biochemical effects.
The origin of the word marijuana is not known but it appears to be the Spanish name for Maria and Juana (Mary and Jane). The drug slang for marijuana includes such names as Mary Jane, pot, grass, tea, reefer (as a cigarette), and weed. In India it is called ghanja, dagga in South Africa, and Kef in Morocco. The potency of the psychoactive cannabinoids found in a marijuana plant varies depending on the locale from which the plant was derived and its genetic makeup.