In the West, traditional Chinese medicine ( TCM 中医学 ) is often considered alternative medicine; however, in China, TCM is widely considered to be an integral part of the health care system. The term TCM is sometimes used specifically within the field of Chinese medicine to refer to the standardized set of theories and practices introduced in the mid-20th century under the government of Mao, as distinguished from related traditional theories and practices preserved by people in Taiwan, Hong Kong and by the overseas Chinese.

TCM developed as a form of noninvasive therapeutic intervention (also described as folk medicine or traditional medicine) rooted in ancient belief systems, including traditional religious concepts. Chinese medical practitioners before the 19th century relied essentially on observation, trial and error. Like their counterparts in the West, they had a very different understanding of infection which predated the discovery of bacteria, viruses (germ theory of disease) or cellular structures and little knowledge of organic chemistry, relying mainly on distinctly observational medical theory describing the nature of infections and remedies actions. Traditions, and observations based on their theory, along with three millennia of practical experience guided their courses of treatment and instruction in diagnostic principles.

Unlike other forms of traditional medicine which have largely become extinct, traditional Chinese medicine continues as a distinct branch of modern medical practice, and within China, it is an important part of the public health care system. There are thousands of years of empirical knowledge about TCM conceptualized and recorded in terms appropriate to that system, and in recent decades there has been an effort to integrate the discoveries made by traditional Chinese medicine with the discoveries made by workers in the Western medical traditions. One important component of this work is to use the instrumentation and the methodological tools available via Western medicine to investigate observations made and hypotheses raised by the Chinese tradition.

That this effort has occurred is surprising to many for a number of reasons. In most of the world, indigenous medical practices have been supplanted by practices brought from the West, while in Chinese societies, this has not occurred and shows no sign of occurring. Furthermore, many have found it peculiar that Chinese medicine remains a distinct branch of medicine separate from Western medicine, while the same has not happened with other intellectual fields. There is, for example, no longer a distinct branch of Chinese physics or Chinese biology.

TCM is used by some to treat the side effects of chemotherapy, treating the cravings and withdrawal symptoms of drug addicts and treating a variety of chronic conditions that conventional medicine is claimed to be sometimes ineffective in treating. TCM has also been used to treat antibiotic-resistant infections.