The eight principle patterns in Traditional Chinese Medicine are used by TCM practitioners to identify and diagnose illness. The patterns are categorized into four pairs of opposites: external and internal, hot and cold, excess and deficiency, and yin and yang.
External and Internal
External and internal patterns identify where in the body the illness is located. External, surface conditions affect the skin, throat, and respiratory tract. They are usually acute conditions, such as fever, sore throat, colds, flu, rashes and other skin eruptions, and headaches.
Internal conditions are generally chronic. They may include problems with the gastrointestinal tract, reproductive system, circulatory system, or internal organs. Some examples are ulcers, menstrual difficulties, diabetes, heart conditions, or cancer. It is possible to have both internal and external patterns at the same time.
Hot and Cold
Whether an individual is hot or cold gives the practitioner a clue about their metabolic processes. Heat is an indication of a fast metabolism, and energy that rises. Heat signs may include a red face, loud voice, irritable or aggressive manner, insomnia, restlessness, high blood pressure, sweating, thirst, scanty dark urine, yellow discharges, fever, constipation, a red tongue and fast pulse. Infection and inflammation also manifest as heat.
Cold signs are indicative of a lowered metabolism and contracting energy. A person exhibiting cold signs may be depressed, lethargic and sleep a lot. Other cold signs include low blood pressure, no sweating, lack of thirst, copious clear urine, diarrhea, clear runny discharges, poor appetite, poor circulation, a pale complexion and pale tongue, and slow pulse.
Not all of these signs will necessarily be present at once, and they may be mild or severe in nature.
Excess and Deficiency
Patterns of excess and deficiency refer to the overall strength or weakness of the individual. Excess patterns are often signs that there is a toxic stagnation or congestion. They may appear as obesity, constipation, high blood pressure, edema or acute infections. Excess patterns are treated with medicinal herbs that eliminate, detoxify, remove stagnation and clear heat from the body.
Deficiency patterns are often seen in people who have a weakened immune system or are sensitive to environmental pathogens or stress. Symptoms may include hypothyroidism, anemia, weakness or fatigue, and poor digestion. Deficiency patterns are treated by tonic herbs that help to build and strengthen the body. It is more difficult to treat deficiency than excess.
Yin and Yang
Yin and yang are two of the most fundamental concepts in Traditional Chinese Medicine, and encompass the other patterns. The characteristics of yin are cool, moist and inward, so yin patterns include internal, cold and deficient features. Yang is warm, dry and expansive, so yang patterns are identified by external, hot and excess symptoms.
Tierra, Lesley. Healing with the Herbs of Life. Berkeley: Crossing Press, 2003.