Significance of "Deqi" response in acupuncture treatment: myth or reality.

Acupuncture has been practiced in China for over 2000 years to treat a variety of diseases based on the "meridian theory," as described in the "Yellow Emperor's Classics of Internal Medicine." Deqi refers to the excitation of qi or vital energy inside meridians by acupuncture needle stimulation. Patients often experience multidimensional and intense needling sensations such as numbness, soreness, distention, heaviness, dull pain, and sharp pain during acupuncture stimulation. Deqi is considered as an important parameter in the process of achieving therapeutic effectiveness in acupuncture treatment. Understanding this phenomenon from neurophysiological aspects is important for clinical practice and enables practitioners to perform quantitative acupuncture evaluation to obtain a reliable prognosis of acupuncture treatment. This review paper describes our current knowledge and understanding of Deqi from a physiological aspect.