Many trials of acupuncture and numerous systematic reviews have recently become available. Their conclusions are far from uniform. In an attempt to find the most reliable type of evidence, this article provides an overview of Cochrane reviews of acupuncture. Such reviews were studied, their details extracted, and they were categorized as: reviews with a negative conclusion (no evidence that acupuncture is effective); reviews that were inconclusive; and reviews with a positive or tentatively positive conclusion.
Thirty-two reviews were found, covering a wide range of conditions. Twenty-five of them failed to demonstrate the effectiveness of acupuncture. Five reviews arrived at positive or tentatively positive conclusions and two were inconclusive. The conditions that are most solidly backed up by evidence are chemotherapy-induced nausea/vomiting, postoperative nausea/vomiting, and idiopathic headache. It is concluded that Cochrane reviews of acupuncture do not suggest that this treatment is effective for a wide range of conditions.