So how does EFT work? Well, simply put no one knows for sure. However there are a few theories. It uses the end points of the 12 major meridian channels and the 2 governing vessels found in Chinese medicine. It has been observed that by tapping on these points while focusing on the problem, a release takes place clearing the physical or emotional pain being worked on. This has lead to the principal that:

The Cause Of ALL Negative Emotions Is A
Disruption In The Body’s Energy System

It seems that while experiencing or focusing on a specific problem, and tapping on the meridians that carry the energy, disruptions are cleared and normal function can resume.