Although it has long been speculated that humans have an ancient history of drug use, there has been a lack of proof to support the theory.
However, now, boffins have found equipment used to prepare hallucinogenic drugs for sniffing, and dated them back to prehistoric South American tribes.
The breakthrough was made by Quetta Kaye, of University College London, and Scott Fitzpatrick, an archeologist from North Carolina State University, on the Caribbean island of Carriacou.
The experts found ceramic bowls, as well as tubes for inhaling drug fumes or powders, which appear to have originated in South America between 100BC and 400BC and were then carried 400 miles to the islands, reports the Telegraph.
While the use of such paraphernalia for inhaling drugs is well-known, the age of the bowls has thrown new light on how long humans have been taking drugs.
Scientists believe that the drug being used was cohoba, a hallucinogen made from the beans of a mimosa species. Drugs such as cannabis were not found in the Caribbean then.
Opiates can be obtained from species such as poppies, while fungi, which were widespread, may also have been used.
Archeologists have suggested that humans were extracting mind-expanding drugs from mescal beans and peyote cacti as far back as 5,000 years ago, but have not found direct evidence that this is true.
They consider that drugs were being used to induce spiritual or trance-like states by people who had religious beliefs.