Placebo controls play a critical role in the evaluation of any pharmacotherapy. 
This review surveys the placebo arm in 12 randomized controlled trials (RCTs) 
investigating burning mouth syndrome (BMS) and documents a positive placebo 
response in 6 of them. On average, treatment with placebos produced a response 
that was 72% as large as the response to active drugs. The lack of homogeneity 
in the use of placebos adds to the difficulty in comparing results and 
aggregating data. Future RCTs investigating BMS would benefit from larger sample 
sizes, adequate follow-up periods, and use of a standard placebo.