According to traditional Chinese medicine (TCM), the head is where the yang meridians of the arms and legs met, and the governor vessel which controls yang qi of the whole body also reaches the head. TCM regards the head as "the confluence of yang". Moreover, essence and blood of the five zang organs and lucid yang (pure essence) of the six fu organs are all infusing into the head, which nourish the brain (sea of marrow) and orifices of the head. The head is closely connected with other parts of the body, and all the organs are responsible for nourishing it. Factors such as abnormal weathers, external pathogens, emotional or organ problems can easily affect the head. Headaches will be triggered when these external or internal factors impede the flow of the meridians, disturb nutrient supply to the head, or block the orifices.

Headache is a subjective symptom and a common pain. It can develop on its own or as a sign of other health problems. Headaches may be caused by problems in the head or elsewhere inside the body. Headaches have numerous causes and can involve different pathological mechanisms, TCM generally classifies into two major categories: exogenous headaches and endogenous headaches.

Exogenous headaches

The headaches are associated with external pathogens. Unhealthy lifestyle or temporary bodily weakness can make the head susceptible to external pathogens. Six pathogens (or evils as they are often known in TCM) may enter the meridians of the head, interrupt the body's yang qi flowing upward, and cause blood and qi stagnated in the head. The headaches are often induced by a combined attack of wind pathogens and other seasonal pathogens, which make the body act differently during the development process. For example, wind along with cold pathogens are likely to enter the blood vessels, lead to a sluggish flow of blood and has a wind-cold headache pattern; wind along with heat pathogens tend to irritate the whole head and make its orifice dysfunction, and thus has a wind-heat headache pattern; wind along with dampness pathogens tend to obstruct the orifices and disturb the yang qi flowing into the head, thus has a wind-dampness headache pattern.

Endogenous headaches

In TCM, the brain is the sea of marrow, which derived from essence and blood of the liver and kidney, and nourished by nutrient essence of the spleen and stomach. Endogenous headaches are associated with internal health problems.

	Depletion of kidney essence or insufficiency of brain marrow makes the head under nourished and dysfunction, leading to symptoms like headaches.
	Emotional upset or stress can lead to liver qi stagnation; as time passes the stagnated liver will generate fire. The fire may attack the head, interrupt its orifices and induce headaches.
	When the spleen is dysfunctional, it cannot transform food and drinks into nutrient essence effectively, there will be inadequate nutrient essence to supply the head and mental activity will weaken. A dysfunctional spleen also produces dampness and phlegm that attack the head orifices directly, and so cause headaches.
	Headaches following head injuries are due to blood stasis formed in the head. Also, long-term and persistent headaches that present with a stabbing pain are related to localized blood stagnation, the collaterals of the head are usually affected.

TCM views on the development of headaches.

Basically, TCM believes that headaches are either due to excessive pathogens that block the collaterals and impair the orifices of the head, or due to insufficiency of essence and blood that fail to nourish and support the brain.

As headache symptoms are manifested in different ways, it will be a great difference in the treatment strategies and drug applications. When making a headache diagnosis, TCM physicians focus on the details such as nature of pain, location of pain, frequency, duration, triggering or aggravating factors, accompanied symptoms, pulse and tongue manifestations. A thorough medical history and physical examination is crucial to identify the headache types and the underlying disharmonies of the body, appropriate treatment plan can then be decided on. Some diagnostic criteria for headaches are listed below.

Differentiation of exogenous or endogenous headaches

Exogenous headaches are usually induced by external factors, present with excess syndromes, that require dispersing the accumulated wind or other pathogens for the treatment. On the other hand, endogenous headaches are mostly due to internal weakness, present with deficiency syndromes or a combination of both excess and deficiency syndromes, that are treated by methods like nourishing, resolving, clearing or subduing to rebuild the internal balance of the body. Once the main category of a headache is clear, the treatment strategy can be determined.

Differentiation of the nature of headache pain

Sometimes, the nature of pain helps understand the cause and underlying disharmony pattern, which provide guideline to decide specific method for relieving headaches.

Differentiation of the location of headache pain

There are many meridians running through the head, which make it closely links up with the rest of body. Based on the order and arrangement of the meridian flow, physicians can identify the internal disharmonies associated with headaches. Locations of headache pain help clarify the involved organs and meridians, and thus determine what specific functions need to be restored.