Another interesting basic theory is the five elements. There are five: fire, earth, metal, water, and wood. It’s an attempt, along with yin and yang, to categorize all phenomena such as illness, moods, organs, tissues, seasons, climate, colors, tastes, and so on, according to a specific element.
The five elements are interconnected and influence each other. It becomes a highly interactive physiological whole of all sorts of functions and phenomena, providing illuminating insights into our functioning.
Wood represents both bending and stretching. It grows upward and spreads outward. It represents growth, upward movement, and freedom from inhibition. It is associated with spring, the time of growth at the beginning of the cycle of the seasons. It is associated with the East, where the sun rises, and with the green color of new leaves and the sour taste of unripe fruit.
The Liver and Gallbladder are associated with the wood phase. The Liver controls the movement of qi throughout the body, spreading qi like a tree spreading its branches. The Liver organizes the recesses and rises like young plants sprouting in spring.
Fire is the upward flame. It is hot and moves upward. It is associated with summer, when the sun’s heat peaks, and with the south, where the sun is at its zenith. It is associated with the color red, and its taste is bitter.
The Heart and Small Intestine correspond to the fire phase. The Heart drives qi and blood through the veins to nourish the body. It is like a fire that warms the body, just as late summer allows nature to grow.
Earth represents sowing and reaping and represents the planting and harvesting of crops and the production of things. It is associated with late summer, when the summer heat ripens the harvest. This is the season between summer and autumn and occupies a central position. Earth is yellow-brown in color and its taste is the sweetness of ripe fruit.
The Spleen is associated with the earth phase and functions to extract nutrients from food. This is traditionally referred to as “transporting and transforming the essence of grains and water.” The earth phase represents the source of qi and blood, which nourish and nourish the body, just as plants are nourished by the earth.
Metal represents change, with qualities such as purifying, eliminating, and reforming. Metal can be shaped and hardened. With metal, humans can harvest and slaughter animals for survival. Killing and purifying also occurs with the first frost in autumn. Metal is associated with the West, where the sun sets, and with the color of frost, white, and the taste of sharp-smelling substances that purify.
The Lung and Large Intestine are connected to the metal phase. The Lung draws in fresh breath and functions to transform the fluids in blood. The Lung also functions to carry fluids down to the Kidney and Bladder and is thus responsible for purifying and eliminating fluids (urine). Therefore, the Lung has the same function as the purifying frost in autumn.
Water is moistening and descends to low places, bringing cold. Water is associated with winter, the season in which nature conserves itself for the next cycle. Water is associated with the North, where the sun does not reach, the darkness of night, and the salty taste of seawater.
The water phase is associated with the Kidney and Bladder. The Kidney sits low, and the body’s fluids flow to it. The Kidney also stores essence (jing), just as nature protects and preserves itself in winter.