In recent decades, numerous clinical trials have been reported; however, only formally published articles that meet one of the following criteria are included in this review:
• randomized controlled trials (mostly with sham acupuncture or conventional therapy as control) with an adequate number of patients observed;
• nonrandomized controlled clinical trials (mostly group comparisons) with an adequate number of patients observed and comparable conditions in the various groups prior to treatment.
In many published placebo-controlled trials, sham acupuncture was carried out by needling at incorrect, theoretically irrelevant sites. Such a control really only offers information about the most effective sites of needling, not about the specific effects of acupuncture (13). Positive results from such trials, which revealed that genuine acupuncture is superior to sham acupuncture with statistical significance, provide evidence showing the effectiveness of acupuncture treatment. On the other hand, negative results from such trials, in which both the genuine and sham acupuncture showed considerable therapeutic effects with no significant difference between them, can hardly be taken as evidence negating the effectiveness of acupuncture. In the latter case, especially in treatment of pain, most authors could only draw the conclusion that additional control studies were needed. Therefore, these reports are generally not included in this review.
The reports are first reviewed by groups of conditions for which acupuncture therapy is given (section 2). The clinical conditions covered have then been classified into four categories (section 3):
1. Diseases, symptoms or conditions for which acupuncture has been proved-through controlled trials-to be an effective treatment.
2. Diseases, symptoms or conditions for which the therapeutic effect of acupuncture has been shown, but for which further proof is needed.
3. Diseases, symptoms or conditions for which there are only individual controlled trials reporting some therapeutic effects, but for which acupuncture is worth trying because treatment by conventional and other therapies is difficult.
4. Diseases, symptoms or conditions in which acupuncture may be tried provided the practitioner has special modern medical knowledge and adequate monitoring equipment.
Section 4 provides a tabulated summary of the controlled clinical trials reviewed, giving information on the number of subjects, the study design, the type of acupuncture applied, the controls used and the results obtained.