What improved Yefet's odds was a dose of dexanabinol, a cannabis derivative being tested by Knoller for an Israeli pharmaceutical company. The new treatment could turn out to be a life saver for tens of thousands of accident victims every year.

Dexanabinol's developers were searching for a way to exploit medicinal powers ascribed to marijuana since antiquity, by using the tools of modern science.

"Cannabis has both good things and bad things and so the idea was how to separate the good from the bad," says Haim Aviv, the CEO of Pharmos, Inc.

They accomplished the feat with a synthetic form of cannabis that's chemically stripped of psychedelic powers - starting with a drug that blows minds and ending up with a medicine that heals brains.

Given within a few hours of a head injury, dexanabinol helps keep the brain from swelling up and literally crushing itself inside the skull. Only a few dozen patients have been treated so far, but a top U.S. brain surgeon says the results are the most promising he's seen in twenty years.

"The pressure inside the head was reduced very dramatically in these patients and that is one thing that we've been looking for and this is most exciting," says Dr. Lawrence Marshall, the head of University of California San Diego's Neurosurgery Department.