For chronic headaches the best treatment may be one of the oldest: acupuncture.

In 1998, the National Institutes of Health accepted acupuncture as a useful alternative treatment for headaches, but warned that there were not enough clinical trials to draw firm conclusions about its efficacy. Now a systematic review of studies through 2007 concludes that acupuncture provides greater relief than either medication or a placebo.

The report, which appears in the December issue of Anesthesia and Analgesia, reviewed 25 randomized controlled trials in adults that lasted more than four weeks. In seven trials comparing acupuncture with medication, researchers found that 62 percent of 479 patients had significant response to acupuncture, and only 45 percent to medicine.

Fourteen of the studies, with a total of 961 patients, compared acupuncture with a placebo, a treatment in which patients were led to believe they were getting acupuncture. Of these, 53 percent found some pain relief with acupuncture, compared with 45 percent who felt better with the placebo. In four studies comparing acupuncture with massage, the massage worked better than acupuncture, but those studies were too small to draw statistically significant conclusions.

“People who get acupuncture prefer it to medication, because of the potential side effects of drugs,” said Dr. Tong J. Gan, a co-author of the review and a professor of anesthesiology at Duke. “This is an alternative treatment that is starting to move into the mainstream.”