Popular drug-free methods of managing pain from such common conditions as headaches and arthritis appear to be effective, according to a new review.

Millions of Americans seek pain relief through such alternatives as acupuncture, tai chi and yoga. But there has been little information to help doctors make recommendations about these approaches.

"For many Americans who suffer from chronic pain, medications may not completely relieve pain and can produce unwanted side effects. As a result, many people may turn to nondrug approaches to help manage their pain," study lead author Richard Nahin said in a U.S. government news release.

"Our goal for this study was to provide relevant, high-quality information for primary care providers and for patients who suffer from chronic pain," Nahin added. He is lead epidemiologist at the U.S. National Center for Complementary and Integrative Health (NCCIH).

Researchers reviewed 105 U.S.-based clinical trials from the past 50 years.

Several alternative approaches showed promise for providing safe and effective pain relief. They included acupuncture and yoga for back pain; acupuncture and tai chi for osteoarthritis of the knee; and relaxation techniques for severe headaches and migraine. Results of massage therapy for short-term relief of neck pain were also promising.

Evidence was weaker in some cases. The study found massage therapy, spinal manipulation and osteopathic manipulation might help relieve back pain while relaxation therapy and tai chi might help people with fibromyalgia.

The study was published Sept. 1 in the journal Mayo Clinic Proceedings.

"These data can equip providers and patients with the information they need to have informed conversations regarding nondrug approaches for treatment of specific pain conditions," said David Shurtleff, the NCCIH's deputy director.

"It's important that continued research explore how these approaches actually work and whether these findings apply broadly in diverse clinical settings and patient populations," he concluded.