The different Tai Chi movements invigorates specific organs. If you for instance have heart problems, one option is to repeat the movement Brush Knee & Push many times to both left & right. Tai Chi affects the body in this manner because it is based on the knowledge accumulated in Traditional Chinese medicine (TCM).
TCM is a system of diagnosis and treatment. In China medical sources excist more than 4000 years old. Through all these years the original knowledge in this medical system has been further developed. The result is that TCM today exist as an integrated medical science, which in many different ways is able to help sick people - also here in the West.
Within TCM the human being exist as an entity, which should be in balance physical and mentally in relation to its surroundings. Is this balance displaced then unbalance is the consequence and may result in sickness. Acupuncture is just a small part of TCM, where doctors also makes use of knowledge of over 2000 herbs and their known effects on the organism, together with a very worked through system of diagnosis, that embrace and determine all known diseases. TCM uses e.g. an advanced kind of feeling the pulse. Hereby the conditions of the inner organs can be precisely confirmed.
What binds the whole TCM system together is the system of diagnosis. The possibility of a very precise diagnosis in connection with herbal medicine may be the most interesting. We already have some knowledge about the effect of different herbs on disease - but this knowledge is stray and more or less fortuitous. On the other hand chinese TCM doctors has succeded, through many years of reserach and gatering of experience, to describe the single herbs very precisely in relation to the diagnosis system. It is thus possible in TCM to prepare a completely individual herbal medicine for each single case of illness.
The TCM doctor makes his diagnosis on the basis of a very thorough conversation with the patient combined with tongue and pulse diagnosis. By comparing all this information the TCM doctor can form a picture of the illness and its individual character, and thus perscribe the correct treatment with acupuncture, herbal medicine or both.
Acupuncture is mainly uses for healing of unbalances in the exterior parts of the body, e.g. muscle pain, back pain, sprains and the like - but you can also heal inner illnesses this way. Today acupuncture is practised all over Europe, though really skilled treatment with herbal medicine is still only available very few places here.
Traditional Chinese Herbal Medicine was developed parallel with acupuncture. Throughout the whole education of TCM doctors the course on the effects and use of herbal medicine is superimposed on the acupuncture section.
For thousands of years doctors of TCM have studied and tested the effect on the body of a large number of herbs. They developed special prescriptions and herbal compounds which heals different diseases, and in course of time herbal medicine and TCM fused into a unity.
Acupuncture therapy often demand several treatments with intervals of a few days - whereas you with herbal medicine can achieve a continuous influence over a longer period of time. For many diseases the herbal medical treatment will be far more effective and direct. This is for instance the case by diseases in the abdomen, the inner organs, by allergy, astma, skin diseases, rheumatism and many other disorders.
When herbal medicine is needed the basis is usually one of the many tested basic prescriptions, which either are used unchanged or are ajusted according to the individual case. This TCM type of herbal medical treatment is very individual, as the medicine is always put together according to each single case.
In China exists herbal pharmacies where the patient hand in his prescription from the doctor, and takes home a bag with the dried herbs. Here the patient makes a decoction of the herbs. For practical reasons in some places you do not use whole herbs, but rather a freeze-dry powder. Many herbs are also prepared in different ways before they are used for medicine. This goes on in China, while the conversion to powder is done on Taiwan. Otherwise the method is precisely the same. The patient gets the herbal powder, dissolves it in boiling water and drinks it as tea.
Below link to a splendid small Youtube-movie with a good introdution to Traditional Chinese Medicine, including the use of herbs, Tai Chi & Qigong.