In Traditional Chinese Medicine (TCM) Theory, the yang ming, which includes the stomach as an organ plus its digestive functions, is one of the six fu organs (along with the Gall Bladder, the Small Intestine, the Large Intestine, the Urinary Bladder, and the three areas within the body cavity collectively referred to in TCM as the Sanjiao --the "tripple warmer." The six fu organs have various roles in the receiving and digestion of foods and liquids, the absorption of nutrient substances, and the transmitting and eliminating of waste. The fu organs may be characterized by their transforming and transporting activities, but they are not considered to be organs of storage.
The Stomach is situated in the middle of the abdomen, below the diaphragm. It receives food at its top through the esophagus, and opens at its bottom to the small intestine. Also referred to as "the sea of water and cereal" in TCM, the main function of the Stomach is to receive and digest food. After digestion in the Stomach, the food is then transported to the small intestine, where the food's essential substances are transformed and transported by the Spleen to the entire body,
Great importance is placed in TCM on diagnosing the strength or weakness of the Qi of the Stomach, since "Stomach Qi is the foundation of the human body: when there is Stomach Qi, there is life: when there is no Stomach Qi, death follows." In other words, if Stomach Qi is strong, the prognosis is favorable, regardless of the disease. Therefore, preserving Stomach Qi is an important treatment principle in TCM.
Since food is passed from the Stomach to the small intestine below it, the normal movement of Stomach Qi is downward. Should it fail to move downward, symptoms such as acid reflux, bloating, stomach pain, nausea, vomiting, and even hiccoughing may arise.