The following is from Wikipedia
EFT was developed by Gary Craig in the mid 1990s, as a simplification and improvement of Roger Callahan's Thought Field Therapy. Having been trained by Callahan in his most advanced procedure, a proprietary procedure known as Voice Technology, Craig eventually simplified Callahan's procedures. EFT has been the subject of three peer-reviewed publications as of 2007.
The first study, published in the Journal of Clinical Psychology in 2003 (indexed in the Medline database) and funded by the Association for Comprehensive Energy Psychology, involved 35 patients with a phobia of small animals receiving a single treatment with EFT.
The authors concluded that:
The findings are largely consistent with the hypothesis that EFT can reduce phobias of small animals in a single treatment session. However, due to methodological limitations in the present study, firm conclusions about the efficacy of EFT must wait for confirmation from future studies. [1]
A second study, published in The Scientific Review of Mental Practice Health in 2003 (indexed in the PsycInfo database), was conducted by Waite and Holder on 119 university students who reported specific fears or phobias.
This study compared four groups: A group that received regular EFT; a second group that tapped on sham points that were not EFT points; a third group that tapped on an inanimate object (a doll) and a fourth group that received no treatment. The first three groups did statistically better than the fourth group, but there were no significant differences between the three tapping groups. That is, the groups that tapped on sham points and on the doll did just as well as the EFT group, but all three groups did better than the no-treatment group. Since the group that used the doll was not tapping on meridian points yet still benefited equally, the authors suggested this as a falsification of the theory that EFT works because of the body's energy meridian system.
A third study, called the SA-45, published in Counseling and Psychology in 2005, involved 102 participants at an experimental EFT workshop. They were tested before the workshop, after the workshop, one month and six months after the workshop.
The only thing the study definitely indicated was that there was a positive effect of attending the workshop.