Acupuncture has been increasingly used as an integrative or complementary therapy for pain. It is well-tolerated with little risk of serious adverse effects. Traditional acupuncture and nontraditional techniques, such as electroacupuncture and dry needling, often result in reported pain improvement. Multiple factors may contribute to variability in acupuncture's therapeutic effects, including needling technique, number of needles used, duration of needle retention, acupuncture point specificity, number of treatments, and numerous subjective (psychological) factors. Controlled trials have been published on pain syndromes, such as acupuncture for acute and chronic low back pain, knee osteoarthritis, headache, myofascial pain, neck pain, and fibromyalgia. For some conditions, enough data are available for systematic evaluations or meta-analyses. Acupuncture may provide modest benefits in the treatment of chronic low back pain, tension headache and chronic headache, migraine headache prophylaxis, and myofascial pain. Although patients receiving acupuncture for acute low back pain and knee osteoarthritis report less pain, the improvement with true (verum) acupuncture over sham acupuncture is not clinically significant for these conditions. These two conditions illustrate a recurring pattern in acupuncture trials, in which the additional improvement that can be attributed to verum over sham acupuncture, even when statistically significant, is of less clinical significance. This pattern supports the notion that acupuncture treatment has a notable placebo response, or meaning response, that may be responsible for much of its demonstrated benefits. For certain patients, especially those who are unresponsive or intolerant to standard therapies, acupuncture is a reasonable treatment option.