A nurse helps a patient to inhale cannabis fumes from a vaporizer at an Israeli nursing home on March 9, 2011. Together with Israel's health ministry, the Tikon Olam company currently is distributing cannabis for medicinal purposes to more than 1,800 people in Israel.

Uriel Sinai/Getty Images

Ancient Times, High Times?

While it's easy to imagine that medical cannabis use got its start in more recent times -- the psychedelic '60s, anyone? -- in reality, people have been using cannabis to help cure what ails them for almost as long as the herb has been in use, period. The earliest records date back to about 2700 B.C., when Chinese physicians were recommending a tea made from cannabis leaves to treat conditions like gout and malaria (cannabis was already in use as early as 4000 B.C. in China as a source of cloth, rope, fiber and cooking oil). Around A.D. 200, Chinese physician Hua Tao wrote about using it as part of what was probably the first anesthetic.

While the earliest mentions of medical cannabis come from China, other regions of the world were not too far behind. Several medical papyri dating from 1000 to 1700 BC show that the ancient Egyptians used cannabis to treat foot and eye problems, as well as hemorrhoids. Separating medicinal use from magical and religious uses can be difficult in ancient literature, however, and this is certainly true in India. The "Atharva Veda," one of the sacred Hindu texts dating to around 2000 B.C., cites it as a sacred plant that combats "evil forces," which include those that cause both spiritual and health problems. More practical uses outlined in later writings like the "Sushruta Samhita" (an Ayurvedic medical text circa A.D. 300) include treating pain, insomnia and headaches, as well as another mention of cannabis as an anesthetic for surgical procedures.

Ancient Greeks may have been influenced by Indian use of medical cannabis, or vice versa. The first written record comes from Herodotus, who stated in 500 B.C. that Scythians, a group of ancient Iranian nomads, took vapor baths using marijuana. Other Greek writers mentioned using it to get rid of tapeworms, stop nosebleeds and reduce inflammation and pain in the ear. The seeds were even prescribed to "dry up semen" of teenage boys, possibly to reduce nocturnal emissions.

The use of cannabis as medicine became hotly debated in Islamic countries in the Middle Ages, as Koranic scholars were unsure whether it was in the same category as alcohol, which was forbidden. Ultimately, they drew a distinction between the use of medical cannabis and hashish (a strong form of marijuana made from resin) as used to get high.

Despite all of this ancient medicinal use, Westerners did not seem to catch on to the concept of medical cannabis until the 1800s, although the plant's other uses had been adopted. Next, we'll look at what most consider the very first scientific study of medical cannabis.