Cannabis wasn’t “discovered” in a single moment. The plant evolved in Central Asia millions of years before humans encountered it, and people in different regions figured out its uses independently over thousands of years. The oldest confirmed psychoactive use dates to around 500 BCE, but humans were cultivating cannabis for fiber and food long before anyone realized it could alter consciousness.
Where Cannabis Originally Grew
For decades, scientists believed cannabis originated somewhere in Central Asia, supported by ancient pollen found in India dating back roughly 32,000 years and in Japan around 10,000 BCE. More recent evidence, including fossil pollen studies, points to the northeastern Tibetan Plateau as the plant’s likely center of origin. Large-scale genetic sequencing of 110 cannabis samples from around the world suggests the plant was first domesticated in East Asia during a much earlier geological period.
Early human communities in East Asia initially grew cannabis for practical reasons. They harvested the oily seeds for food and eventually processed the long, durable stem fibers into clothing and cordage. For centuries, the plant was essentially an agricultural crop, not a drug. The shift toward psychoactive use happened separately, in a different part of the continent.
The Earliest Psychoactive Use
The oldest scientifically verified evidence of people using cannabis to get high comes from the Jirzankal Cemetery, perched 3,000 meters up in the Pamir Mountains of far western China. A team led by archaeologists Yang Yimin and Ren Meng of the Chinese Academy of Sciences analyzed residue from wooden braziers (small fire containers) found in the tombs, dating to roughly 500 BCE. Using gas chromatography and mass spectrometry, they detected unusually high levels of THC compared to typical wild cannabis plants.
The cannabis had been burned inside enclosed spaces during funeral ceremonies, meaning mourners almost certainly inhaled the psychoactive fumes. The chemical signature also suggests these weren’t just wild plants picked off a hillside. The THC levels indicate the cannabis may have been selectively bred or hybridized, an early form of domestication aimed at producing stronger effects.
This wasn’t the first claim of ancient cannabis burning in Central Asia. Earlier researchers had pointed to sites as old as 5,000 years, but reanalysis of those plant remains showed they contained very low THC, meaning they likely had no mind-altering properties. The Jirzankal findings are different because the chemistry holds up.
A separate discovery at the Jiayi Cemetery in Turpan, dating to roughly 800 to 400 BCE, turned up 13 desiccated cannabis plants used as a burial shroud. Chemical analysis of those plants also showed elevated levels of psychoactive compounds. Together, these finds place the earliest intentional use of high-THC cannabis in western China or the broader Central Asian region.
Early Medicinal Records
The first known pharmacopoeia, the Chinese “Shen Nung Pen Ts’ao Ching,” compiled around the first century BCE, included cannabis among its remedies. It referenced the plant’s anti-inflammatory, antiseptic, and anticonvulsant properties, though these texts were compiled from oral traditions that may stretch back further.
Ancient Egyptian medical texts also document therapeutic cannabis use. The Ebers Papyrus, dating to roughly 1600 to 1550 BCE, includes a recipe for ground cannabis mixed with honey, inserted vaginally to reduce uterine inflammation. Several other Egyptian papyri, including the Papyrus of Ramesses III and the Berlin Papyrus, mention cannabis-based medicines as well. These records show that by the second millennium BCE, healers across multiple civilizations had independently recognized the plant’s medicinal value.
How Cannabis Spread Across the Ancient World
Cannabis reached the South Asian subcontinent between 2000 and 1000 BCE, carried by the Aryans, an Indo-European group that migrated into the region. It arrived in the Middle East between 2000 and 1400 BCE, likely spread by the Scythians, nomadic Indo-European traders and warriors. The Jirzankal Cemetery itself shows signs of this interconnected world: glass beads from Western Asia and Chinese silk were found among the graves, and isotopic analysis of 34 skeletons revealed that nearly a third of the people buried there were migrants from elsewhere.
This pattern of long-distance trade and migration carried cannabis steadily westward and southward over the following millennia. By the time classical Greek and Roman writers mentioned the plant, it was already well established across a vast geographic range.
Arrival in the Americas
Cannabis reached the Western Hemisphere with European colonizers. The Spanish began cultivating it in Chile around 1545, and early Spanish explorer Álvar Núñez Cabeza de Vaca, traveling between 1527 and 1537, described native peoples using a “certain smoke” that produced intoxication. Cannabis was introduced to Brazil either by Portuguese colonists or by enslaved Africans in the early 1800s.
The word “marijuana” itself reflects this tangled colonial history. It first appeared in print in the 1846 “Farmacopea Mexicana,” spelled “mariguana.” Its deeper origins are debated. One theory traces it to the Nahuatl word “mallihuan,” meaning prisoner. Another links it to Mexican street herbalists called “Marias” and revolutionary soldiers called “Juanes.” A third theory, proposed by geographer Chris Duvall, connects it to the Kimbundu (Angolan) word “mariamba,” carried to the Americas by enslaved people from Central Africa. The spelling with a “j” appears to be an English innovation, and the word didn’t enter English until the late 19th century.
When Science Caught Up
Despite thousands of years of human use, nobody understood why cannabis affected the mind until remarkably recently. The main psychoactive compound, THC, wasn’t isolated and identified until 1964, when Raphael Mechoulam and Yechiel Gaoni accomplished it at the Weizmann Institute in Israel. This was a major reason cannabis had been difficult to study or standardize as medicine: without knowing the active ingredient, researchers couldn’t measure doses or design reliable experiments. Mechoulam’s work eventually led to the discovery of the body’s own endocannabinoid system, the network of receptors that THC activates, which wasn’t mapped until the 1990s.
So the story of cannabis “discovery” stretches from prehistoric farmers selecting seeds on the Tibetan Plateau to funeral mourners inhaling smoke in the Pamir Mountains to a 20th-century lab in Israel finally explaining, at the molecular level, what humans had known from experience for at least 2,500 years.