A British company is conducting landmark trials which could see medicines derived from or inspired by the cannabis plant itself making their way to American pharmacy shelves.
GW Pharma is in advanced clinical trials for the world's first pharmaceutical developed from raw marijuana instead of synthetic equivalents -- a mouth spray it hopes to market in the US as a treatment for cancer pain.
The firm hopes to receive US government approval by the end of next year.
The trials come a quarter of a century after the US Food and Drug Administration (FDA) approved the first prescription drugs based on the main psychoactive ingredient in marijuana.
Sativex contains marijuana's two best known components -- delta 9-THC and cannabidiol -- and has already been approved in Canada, New Zealand and eight European countries for relieving muscle spasms associated with multiple sclerosis.
FDA approval would represent an important milestone in the United States' often uneasy relationship with marijuana.