Many studies of acupuncture treatment are seriously flawed by methodological problems. Poor design, inadequate measures and statistical analysis, lack of follow-up data and sub-standard treatment are all too common. However, the major problem, which many investigators consider to be still unresolved, is the definition of an appropriate placebo control. The use of inappropriate placebo controls has bedeviled acupuncture research and led to serious misinterpretation of the results of clinical trials. While a number of different solutions have been proposed there is, as yet, no agreed way of assessing the adequacy of control conditions or of deciding which placebo to use in a particular trial. We propose that assessing the credibility of treatments and control conditions may provide a way forward to a more rigorous, consensus approach.