Some leading medical experts in the U.S. are calling it a breakthrough cure.
A growing body of research suggests the psychedelic drug, MDMA, is highly effective in treating Post Traumatic Stress Disorder, or PTSD, in military veterans, rape victims and other adults.
MDMA has a party-reputation as the euphoric "club drug," used by scantily-clad crowds at raves, concerts and electronic dance festivals. Its street names are ecstasy and "Molly."
The DEA also keeps it closely in its cross hairs in the war on drugs.
But, on a much different war front, soldiers and others are often returning with severe PTSD and other mental health illnesses.
"People shot up, blown up, whatever," said veteran Army medic James Casey. "Kids get caught in the crossfire as well."
Casey shipped off to Afghanistan when he was just 18 years old. He spent a year there and returned very ill.
"I just had this really dark side of me," said Casey.
Casey said he often had trouble controlling his anger -- taking it out on his wife, his family and a few really troubling behavioral incidents with his new puppy.
"I would end up choking her until her eyes would roll in the back of her skull," said Casey. "And I didn't even realize I had a problem."
Although never violent with people, Casey feared it would come to that, so he sought out treatment for PTSD.
"I did nearly every single other treatment for PTSD that the Department of Defense sponsored," said Casey. "And nothing helped."
Then, he found MDMA.
"I really had nothing to lose," said Casey.
The U.S. government banned MDMA in the 1980's. But recently, a small band of medical researchers - including a few in Boulder, have wrangled permission from the U.S. government to try the drug as medical treatment again.
This time - administering it to patients suffering from PTSD and other illnesses.
"So people are able to look at traumatic memories, the fear is reduced and then they're able to separate out that it was happening then and not now," said Rick Doblin, with MAPS, the Multidisciplinary Association for Psychedelic Studies.
Patients like Casey undergo three separate treatments.
While lying down on a couch, blindfolded - they take the drug and then therapists guide patients through their worst fears.
"We're saying that MDMA itself is not the medicine," said Doblin. "It's MDMA-assisted psychotherapy."
"The MDMA was like armor that I put all over my body so that I could dive into the darkness of my PTSD, and then come back unscathed," said Casey.
The sessions are grueling. Sometimes 8-10 hours until the drug completely wears-off.
"Me trying to get better by myself was like I was lost in a cave with no light," said Casey. "The MDMA was like light for me to see all throughout this cave. And the therapists were like guides."
For this baby-faced war vet - the illegal street drug has been a miracle cure.
"It blows every single other treatment for PTSD out of the water," he said. "It's like a dream come true."
Other vets, like Ryan LeCompte, who turned to alcohol after the Marines, are believers as well.
"I was a skeptic. I didn't touch psychedelic drugs," said LeCompte. "That's a miracle to me."
Experts agree. In phase two of the three-phase, non-profit study, research shows nearly 83 percent of patients are cured - meaning no recurrence of PTSD or other illnesses one year after treatment, according to the Journal of Psychopharmacology.
That compares to a 25 percent success rate in other treatments.
The study includes not only war vets, but rape victims and others.
"I'm grateful that I do have my life back," said Casey. "I do love my wife. I do love my family. I love that little dog that I got."
Researchers with MAPS are now entering the third and final phase of the $21-million dollar FDA-approved study.
If phase three is as successful as phases one and two, the FDA could approve the medication for legal use in the U.S. by 2021.