One of the basic tenets of TCM is that "the body's vital energy (ch'i or qi) circulates through channels, called meridians, that have branches connected to bodily organs and functions." Concepts of the body and of disease used in TCM reflect its ancient origins and its emphasis on dynamic processes over material structure, similar to European humoral theory. Scientific investigation has not found histological or physiological evidence for traditional Chinese concepts such as qi, meridians, and acupuncture points. The TCM theory and practice are not based upon scientific knowledge, and there is disagreement between TCM practitioners on what diagnosis and treatments should be used for any given patient. The effectiveness of Chinese herbal medicine remains poorly researched and documented. There are concerns over a number of potentially toxic plants, animal parts, and mineral Chinese medicinals. There are also concerns over illegal trade and transport of endangered species including rhinoceroses and tigers, and the welfare of specially farmed animals including bears. A review of cost-effectiveness research for TCM found that studies had low levels of evidence, but so far have not shown benefit outcomes. Pharmaceutical research has explored the potential for creating new drugs from traditional remedies, with few successful results. A Nature editorial described TCM as "fraught with pseudoscience", and said that the most obvious reason it hasn't delivered many cures is that the majority of its treatments have no logical mechanism of action. Proponents propose that research has so far missed key features of the art of TCM, such as unknown interactions between various ingredients and complex interactive biological systems.
The doctrines of Chinese medicine are rooted in books such as the Yellow Emperor's Inner Canon and the Treatise on Cold Damage, as well as in cosmological notions such as yin-yang and the five phases. Starting in the 1950s, these precepts were standardized in the People's Republic of China, including attempts to integrate them with modern notions of anatomy and pathology. In the 1950s, the Chinese government promoted a systematized form of TCM.
While health is perceived as the harmonious interaction of these entities and the outside world, disease is interpreted as a disharmony in interaction. TCM diagnosis aims to trace symptoms to patterns of an underlying disharmony, by measuring the pulse, inspecting the tongue, skin, and eyes, and looking at the eating and sleeping habits of the person as well as many other things.
Traces of therapeutic activities in China date from the Shang dynasty (14th–11th centuries BCE). Though the Shang did not have a concept of "medicine" as distinct from other fields, their oracular inscriptions on bones and tortoise shells refer to illnesses that affected the Shang royal family: eye disorders, toothaches, bloated abdomen, etc., which Shang elites usually attributed to curses sent by their ancestors. There is no evidence that the Shang nobility used herbal remedies. According to a 2006 overview, the "Documentation of Chinese materia medica (CMM) dates back to around 1,100 BCE when only dozens of drugs were first described. By the end of the 16th century, the number of drugs documented had reached close to 1,900. And by the end of the last century, published records of CMM had reached 12,800 drugs."
Stone and bone needles found in ancient tombs led Joseph Needham to speculate that acupuncture might have been carried out in the Shang dynasty. This being said, most historians now make a distinction between medical lancing (or bloodletting) and acupuncture in the narrower sense of using metal needles to treat illnesses by stimulating specific points along circulation channels ("meridians") in accordance with theories related to the circulation of Qi. The earliest evidence for acupuncture in this sense dates to the second or first century BCE.