Traditional Chinese Medicine (TCM) has a written history of nearly 3000 years, and there are indicators that it has been practiced long before that. In the beginning the instruments used for acupuncture were made of stones known as Bian stone. Over time, as technology advanced, iron needles replaced stone, and then they were replaced by metal medical needles. This broadened the field of acupuncture and its many applications. Documents outlining the meridians and collaterals (channels where Qi (chee) travels) were discovered that date back to the 3rd Century B.C.
Huangdi's Internal Classic, written between 770-221 BC, layed out the theorectical foundation of TCM. It included the theories of yin-yang, five elements, zang-fu, meridians and collaterals, mentality and spirit, qi and blood, body fluids, five emotions and six exogenous pathogens. It explained human physiology, pathology, diagnostic principles, as well as prevention and treatment of disease with acupuncture and moxibustion (a herbal warming technique). This book continues to be studied by practitioners today and is still applicable to modern day treatment of diseases.