ObjectivesThe validity of a new sham acupuncture technique was tested on acupuncture naïve healthy subjects. Methods The procedure was tested in accupoints LI4 and ST6 in a randomised, single blind and crossover study. The participants were blind to which technique they received. 32 healthy volunteers (15 men, 17 women, aged between 20 and 62 years, mean age 34 years) were recruited at the Universidad de la República, Uruguay. Interventions Participants were randomly assigned to one of two groups: (1) real acupuncture or (2) sham acupuncture. After 30 min, the patients were 'needled' again in a crossover design. Main outcome measures A yes/no questionnaire was used to assess the credibility and characteristics of the procedure. Results For the credibility question (do you think you received real acupuncture?) no statistically signifi cant group differences were evident before or after the crossover. Subjects who answered yes to this question ranged from 14/16 (87.5%) before crossover to 10/16 (62.5%) after crossover for the sham and 12/16 (75%) before crossover to 15/16 (93.8%) after crossover for the real acupuncture. The question that showed a signifi cant difference (only after crossover) was the question, "did you feel the needle penetrating the skin?"; after crossover 12/16 (75%) subjects in the real acupuncture group said yes and 2/16 (12%) subjects in the sham group said yes to this question (p<0.01). Conclusions These data suggests that this method is credible and constitutes a simple and inexpensive technique for use as a control in clinical research in acupuncture naïve subjects. INTRODUCTIONEvidence based medicine requires well-controlled research studies with adequate placebo techniques that mimic all aspects of the active intervention but are inert. Acupuncture therapy is used world wide for the treatment of several diseases but the lack of research studies with acceptable controls has been a major methodological problem. The lack of adequate sham procedure in the past has led researchers to compare real acupuncture with a wide variety of other interventions. For example, it is still common to see published peer-reviewed research in which the sham procedure consists on needling non-acupuncture points or minimal subcutaneous stimulation in acupuncture points.3 4 It was argued that procedures which imply needle insertion are not acceptable as controls because they can elicit neurobiological responses at various levels in the central nervous system, including the primary and secondary somatosensory cortex, anterior cingulated cortex and the insula region. 6The National Institutes of Health already recognised this methodological problem a decade ago during the Consensus Conference on Acupuncture 1 and concluded that "Although there have been many studies of its potential usefulness, many of these studies provide equivocal results because of design, sample size, and other factors". Furthermore, it was specifi cally stated that the lack of appropriate controls such as placebos and sham acupunctur...