Marijuana was described in
Indian and Chinese medical texts more than 3,000 years ago. It was used to treat conditions such as beriberi, constipation, gout, malaria, rheumatism, and absent-mindedness, as well as depression, insomnia, vomiting, tetanus, and coughs.
In the middle ages, herbalists used it externally to help muscle and joint pain.
In the mid-1800s, the plant was mentioned as a treatment for gonorrhea and angina (chest pains related to heart disease). It was also used to treat intestinal pain, cholera, epilepsy, strychnine poisoning, bronchitis, whooping cough, and asthma. In the US and Europe, marijuana extracts were prepared and sold for medicinal use as sedatives and pain relievers, to help appetite and sexual problems.
Things were already changing in the US in 1937, when marijuana use (even by doctors) was taxed. Then Congress passed a law in 1951 that classified marijuana as a narcotic drug. In 1970, marijuana was defined in a new law, the Controlled Substances Act, as a Schedule 1 drug -- a drug with no accepted medical use and with the potential for abuse.
Marijuana is legal in many parts of Asia and the Middle East
In recent decades, marijuana has been the subject of extensive medical research using more advanced methods of testing as specific active compounds have been isolated. But political and legal controversies surrounding its status as an illegal substance, as well as concerns about potentially harmful side effects, have hampered the process of scientific inquiry in many countries, including the United States.
Despite this, researchers continue to study the compounds in marijuana for possible medical applications.
Two prescription drugs based on marijuana compounds have been approved in the United States, and a third has been approved in Canada and Europe. The prescription drug dronabinol is an active ingredient of marijuana. It is used for patients with chemotherapy-related nausea and vomiting that does not respond to usual treatments, as well as for people with serious weight loss due to AIDS. Nabilone is another drug based on cannabinoids that is used for nausea and vomiting after chemotherapy. Other compounds are being tested for possible use as drugs.
More recently, scientists reported that THC and other cannabinoids such as CBD (cannabidiol) slow growth and/or cause death in certain types of cancer cells growing in laboratory dishes. Some animal studies also suggest certain cannabinoids may slow growth and reduce spread of some forms of cancer.