Cannabis sativa is an annual herb in the family Cannabaceae which grows 3-10 feet tall and has hairy leaves divided into 5 to 7 serrated leaflets; the leaves are often sticky with resin. The plants are distinctly male or female (male and female flowers are produced by separate plants) and they flower from June to October.
Hemp is one of the oldest and one of the most all-round useful economic plants. Its fibers have been used to make high-quality paper, rope, twine, and cloth (the original Levi's jeans were made from hemp); its seeds have been eaten as a high-protein grain, turned into a tofu-like nondairy cheese substitute, and pressed to make oil for paints and varnishes; its leaves and flowers have been eaten or smoked as a medicine or intoxicant.
It was originally native to the Caucasus region of far eastern Europe, northern India, and Persia (Iran) but it is now cultivated in warm-to-temperate regions all over the world. Archaeologists have found 10,000-year-old pot shards imprinted with hemp fibers. The Chinese documented its medicinal values over 4,000 years ago; they used the seeds to treat pain, fever, ulcers, nausea, and many other ills. The Arabs started using the plant at least by the mid-1200s, and they in turn introduced it into Africa in the 1500s and 1600s. Pollen records from lakebed sampling indicate that hemp was grown in England as early as 800 A.D. and in Scotland as early as 1000 A.D. Hemp production in the British Isles waxed and waned as other crops fell in and out of favor, but evidence indicates it was an important crop there throughout the Middle Ages up into the 19th Century. Continental Europe discovered hemp incrementally, and hemp production got a big boost after Marco Polo's return from his journey to the East in 1297; later, Crusaders brought back stories and seeds from the Middle East. It was introduced to South America in 1545 by the Spaniards, and the British started growing hemp in Jamaica and the New England colonies in the early 1800s.
It was legal in the U.S. until the 1920s and 1930s, when several factors led to its criminalization: legitimate concern over addiction, an anti-marijuana crusade begun to justify the existence of the new federal Narcotics Bureau, and racism (Cannabis smoking was a popular theme in African-American and Latino jazz music of the era). As a result, under the Controlled Substances Act, hemp/marijuana was classified as a Schedule I controlled substance and was totally banned in the U.S., regardless of its narcotic content. However, before the ban it was widely grown, and and in many places in rural areas of the U.S. hemp grows as a common weed.
Since 1990, varieties of hemp that mostly lack tetrahydrocannabinols (its medicinal/intoxicating compounds) have been legalized in Great Britain, Germany, Austria, and Switzerland. Canada and Australia legalized hemp production in 1998. Countries such as China, Russia, and Hungary never outlawed hemp production.
Because the U.S. imports so many hemp fiber goods (over 1.5 million pounds of the raw fiber alone in 1999), many agricultural states see hemp production as a lucrative endeavor. The governor of Kentucky established a Hemp and Related Fiber Crops Task Force in 1994. In 1999, Arkansas, California, Hawaii, Illinois, Minnesota, Montana, New Mexico, North Dakota, and Virginia passed legislation to promote research into hemp as a crop; at the end of that year, the first test plots of industrial hemp in the U.S. were planted in Hawaii.
Aside from its well-known intoxicating properties, the tetrahydrocannabinols (THCs) in hemp have documented medicinal value. Its leaves and sap have been universally used as a painkiller and sedative, and its roots were used by ancient herbalists to make salves for burns and other wounds. In 1965, scientists isolated THC and later discovered that the compound can lower pressure in the eyes of glaucoma patients and has thus far been an excellent drug for glaucoma treatment. They also discovered THC dilates bronchial tubes and can therefore benefit asthma sufferers.
Later, they discovered that THC has antispasmodic properties that could possibly benefit people with epilepsy and people with multiple sclerosis who suffer from tonic spasms. People suffering from chronic pain from joint injuries have also found relief by smoking marijuana.
And finally, THC has proven to give relief to patients undergoing chemotherapy by helping to alleviate the nausea they often suffer (synthetic THC is sold as highly-controlled prescription medication under brand names such as Marinol). Many AIDS and cancer patients have found it stimulates their appetite, thus combatting the wasting associated with their illnesses.
A federal study in 1972 and a study by the National Academy of Sciences in 1981 both recommended that Cannabis use be decriminalized. The latter study found that although immediate use causes mental impairment and heavy, long-term use causes physical problems and possibly an increased risk of lung cancer (the potential carcinogenicity due to smoke inhalation rather than any compound specific to marijuana), they could determine no long-term ill effects for occasional, light users and concluded that on the whole marijuana was no more dangerous than alcohol and tobacco.
References:
1995 Physician's Desk Reference ©. Montvale, NJ, Medical Economics Data Production Company.
Dobelis, Inge N., ed. 1989. Magic and Medicine of Plants. Pleasantville, NY, Reader's Digest Books.
Simpson, Beryl Brintnall and Molly Conner-Ogorzaly. 1986. Economic Botany: Plants in Our World. New York, NY, McGraw-Hill Publishing Co.
http://www.ers.usda.gov/publications/ages001e/
http://www.druglibrary.org/schaffer/hemp/medical/ms_mj_ref.htm
http://www.ukcia.org/newsite/culture/history/hmpukhis.html
