Traditional Chinese Medicine is a broad range of medicine practices sharing common concepts which have been developed in China and are based on a tradition of more than 2,000 years, including various forms of herbal medicine, acupuncture, massage (Tui na), exercise (qigong), and dietary therapy. It is primarily used as a complementary alternative medicine approach. TCM is widely used in China and it is also used in the West.TCM "holds that the body's vital energy (chi 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 origins in pre-scientific culture, similar to European humoral theory. Scientific investigation has found no 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 its own practitioners disagree widely 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. 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 why 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.