Los Angeles study.  Dr. Mohab Ibrahim and Rajesh Khanna tested green LED lights and white LED lights on a small sample of people with chronic migraines.  Participants in the trial were asked to starte at the lights for 1-2 hours a day over a 10 week period.  The green lights proved to be succssful, reducing migraine pain 40 to 50 percent.

Participant Debi Lesneski:

"It was one migraine right after another," she said. "There was no break in between."

She was depressed, sick and unable to get out of bed on some days. Lesneski said she was doubtful when joining the clinic trial, but was willing to try anything.

"(I was) very skeptical because it is so simple," she said. "It doesn't make any sense that just some light can fix a problem that modern medicine can't even address. And, it worked."

..

Even Lesneski wanted to keep her light. Now, she uses the green light for 15 minutes, three times a week and has stopped taking her pain medications.

(via "Doctors find new ways to treat migraine pain with green LED lights", ABC 7 News)

How it works?  There might be a psychological factor to it...

Even though the correlation of the green light and migraine pain is unknown, Ibrahim said it could be partially psychological.

"Regardless of the mechanism, the outcome is what really matters," said Ibrahim, director of the Chronic Pain Clinic. "People are both feeling better and their pain is getting better."

The green lights help regulate brain chemistry, Khanna said.

"Essentially, what it's doing is increasing your happy hormones, your level of endogenous opioids," he said.

Khanna, a professor of pharamcology at the University of Arizona, said that besides happy hormones, it also made for happy patients.

"The people in the green light group, they actually refused to return the green lights, and they wanted to keep it, so we let them keep it," he said.