Si qi wu wei 
refers to the four properties and five flavours of Chinese medicines.Gui jing 
refers to the function of Chinese medicines, andsheng jiang fu chen 
refers to the direction where the drugs are taking effects.
Four properties (si qi 
)
This refers to the four properties of Chinese medicines. Known also assi xing 
, they are the cold, hot, warm and cool nature of medicines. Besides the four properties, there is also mild nature (ping xing 
), a term used when it is unclear whether the medicine has a cold, hot, warm or cool nature, or if it has a mild effect.
- “Cool medicines”: used for clearing away heat, purging fire, detoxifying and nourishingyin. E.g. gypsum
, honeysuckle flower 
, goldthread rhizome 
, ophiopogon root 
, etc. - “Mild medicines”: refers to medicinal materials of mild properties that are warm but not dry, cool but not cold. E.g. pilose asiabell root
, bupleurum root 
, etc. - “Warm-heat medicines”: used for expelling cold, clearing blood vessels, invigoratingyang andqi. E.g. prepared aconite branch-root
, evodia fruit 
, astragalus root 
, Korean ginseng 
, etc.
The Four Properties
Five flavours (wu wei 
)
This refers to the authentic flavour of the medicine and food. Also known as the tastes of Chinese medicines, they include sour, bitter, sweet, pungent and salty, which are the five basic flavours. They are usually called “the five flavours of medicines”. Actually, there are more than five flavours of medicines and food, e.g. mild-flavoured, and astringent. The latter is classified as a sour flavour, while the former is considered to be a type of sweet flavour.
The Five Flavours
Fast facts
About the “five properties (wuxing )
Li Shizhen 
was the person who first mentioned the “five properties (wuxing 
)” of Chinese medicines, namely the cold, hot, warm, cool and mild natures. As the mild property is considered to be subjective, the term “four properties (siqi 
)” has been used in the pharmaceutical field to the present day.
Meridian tropism (gui jing 
)
The meridians through which the therapeutic action of drugs is manifested. This is known as meridian tropism (gui jing 
). Gui 
is the classification of drugs according to their effects. Jing 
is a general term used to refer to the meridians of organ systems. With the knowledge of meridian tropism, we are able to identify the exact therapeutic effects a Chinese medicine has on specific internal organs and meridians. Thus, we can choose to use certain Chinese medicines to treat pathological changes in a specific body part, bringing about main and specialised therapeutic effects. The therapeutic effects of medicines differ with different meridians. The understanding ofgui Jing 
thus enables us to improve the accuracy with which we apply medicines.
Direction of medicinal action (sheng jiang fu chen 
)
This refers to the direction of the action of drugs.
Sheng 
, which means ascending, refers to drugs with an upward effect, used to treat illness of descending condition.Jiang 
, which means descending, refers to drugs with a downward effect to treat illness of ascending condition.Fu 
, which means floating, refers to drugs which have an outward effect to cure external illness.Chen 
, which means sinking, refers to drugs having an inward effect to cure internal sickness.
The Direction of Medicinal Action
Fast facts
“Meridian guiding action 
” or “herbs for meridian guiding 
”
Chinese medicinal materials seldom belong to only a single classification, e.g. pilose asiabell root 
grouped under both the spleen and lung meridians. This implies that the herb can replenish both lung and spleenqi. Liquorice 
and prepared aconite branch-root 
are able to pass through 12 meridians. Yet other Chinese medicines are not classified under any meridian, but can guide other medicinal materials to enter certain meridians. These herbs are called “herbs for meridian guiding(yin jing yao 
)”. E.g. achyranthes root 
can guide medicines downwards, and cinnamon twig 
can guide medicines into the heart meridian.