The functions of the Stomach and Spleen start after birth, so they’re the ‘Roots of the Post Heaven Qi’. The functions of the Stomach include; food storage, the origins of the 5 tastes, appetite and receiving food. The Stomach is also known as the ‘Great Granary’ or a sea of Qi since the Pharynx and Esophagus send food and liquids to it.
A good appetite means a strong sense of receiving from the Stomach. The absence of it points to a collapse in receiving from the Stomach. When Stomach-Qi rebels, it travels upward where the organism experiences nausea and vomiting.
Rotting and Ripening Food
The Middle Burner is also known as the ‘bubbling cauldron’ because the Stomach ferments food in order to ripen and rot it. Fermentation sets the basis for the functions of the Spleen as it extracts essences from food. Once food is transformed, the Stomach the sends it to the Small intestine for further processing.
A healthy Stomach is essential for the 5 Yin organs that derive Qi from it. Traditional Chinese Medicinal theories take the Stomach and the Spleen to be the origin of Qi within the body. The absence of Stomach/Spleen Qi reduces the likelihood of avoiding illnesses and possible association to death.
Tonifying the Stomach and the Spleen tonifies life through ST-36 Zusanli and SP-6 Sanyinjiao that tonifies blood and Qi.
Transportation of Food Essences
Both the Spleen and the Stomach are interdependent as they manage food essence throughout the body. A strong Stomach contains powerful Qi to transport food essences and fuel the body with energy. Contrarily, a deficient Stomach will cause tiredness and weakness in the muscles. The limbs will be weak specifically in Stomach and Spleen Deficiency.
The organs are dependent on the Stomach-Qi to reach the Lung channel and the pulse. A harmonized pulse indicates a strong Stomach Qi, while a fast and abnormal pulse indicates a lack of it.
The tongue coating is the dirty dampness of the fermentation process that manifests on the tongue. When the Stomach and the Stomach-Qi are well, the coating on the tongue will appear thin and white. If Stomach-Qi is weak, digestion is impaired and the tongue will appear to have no coating. If the color of the tongue is thicker and whiter than usual, the Stomach is experiencing Cold. However, if the coating is yellow, the Stomach experiences Heat.
Controlling the Descending of the Qi
Food is transformed down to the Small Intestine, so the Stomach Qi descends to enable the smooth flow of digestion. When the Stomach-Qi fails to descend, food will be retained in the stomach causing nausea, regurgitation and a feeling of fullness.
Though the Stomach is a Yang-organ and the Spleen is a Yin-organ, they are both an Earth element. Their location as an Earth element is in the center of the body, or the Middle Burner. Spleen Qi is sent up and the Stomach Qi is sent down.
The Liver contributes to the descending of the Stomach-Qi and aids digestion. If the Liver-Qi remains stagnant in the Middle Burner, the Stomach-Qi will not descend properly, causing vomiting and nausea.
The Origin of Fluids
The foods and liquids processed within the Stomach create Body Fluids. These fluids continue the cycle of breaking down other food and extract the essentials of herbal decoctions. Oftentimes eating at night causes fluid deficiency where digestion will be impaired and the body experiences constant thirst.
The Kidneys or the ‘Gate of the Stomach’ transform fluids. If they cannot transform fluids in the Lower Burner, they overflow to the Middle Burner and stop digestion. Conversely, if the Stomach can’t produce fluids for a long period of time, the Kidney-Yin will be deficient.
The channel deriving from the Stomach is in front of the body making it a Yin channel, even though it is a Yang organ.
The Spleen relies on the fluids of the Stomach to transport and transform essences and the Stomach relies on the Spleen to transform and separate Body Fluids. They heavily rely on each other in the Middle Burner in order to perform correctly.
Fire agitates the Mind, and the Stomach is prone to excess patterns such as Fire. In excess, the Stomach causes mild manic behavior. For example, the desire of isolation, violence, uncontrolled speaking, laughing or singing and the impulsive desire to take clothes off. In lighter cases the Mind enters mental confusion, hyperactivity, hypo-mania and anxiety. When the Stomach enters deficiency, dreams include eating a large meal.