What are the "four natures" and the "five flavors?"What are the lifting, descending, floating and sinking effects of TCM medicines?

 Q : What are the "four natures" and the "five flavors?"

 
A: The four natures in Chinese medicine are "cold, cool, warm and hot". The five flavors are "sour, bitter, sweet, spicy hot and salty". TCM believes that since Chinese medicines have such different properties they have different effects and can work on specific organs or meridians. For example, hot and spicy medicines like ginger and onion make one sweat; sweet-tasting herbs like red dates and pilose asiabell root have tonifying effects. Clinically, people with a dry throat and bitter taste in their mouth are regarded as having excessive heat inside their bodies; they need to take medicines that are relatively cold and cool. People who tend to suffer from internal coldness need to ingest medicines that are relatively warm and tonifying. 
Q : What are the lifting, descending, floating and sinking effects of TCM medicines?
 
A: These different "spatial" effects reflect the effects of tendencies of Chinese medicines. A "lifting" effect enables the medicinal properties to move from the lower region towards the upper region; a "descending" effect enables the medicinal properties to descend to the lower parts of the body; a "floating" effect drives the medicinal properties to reach the different parts of the body or to move from upper to the lower region; while a "sinking" effect means consolidating and restricting, enabling the facilitation of urination and defecation. Since different diseases have various developmental tendencies (moving upwards, downwards, spreading outwards and moving inwards), medicines that can match the conditions of these diseases or improve on or eliminate their symptoms are used. For example, for Influenza (common cold), TCM believes that the position of the disease lies on the upper part and on the exterior, and then it is appropriate to use medicines that have the nature of rising and dispersing, such as ephedra and cassia twig, medicines that have descending and sinking natures should not be used.