That which is the stomach and spleen is the minister of granaries, the five flavors emanate from it.” This statement from the Neijing is very profound in that it sets in motion the basic physiology of the digestive system, but also that of all herbal treatment. The “five flavors” are more than just flavors, they are the energetic components that make up everything we ingest, from food to medicine. In seeing we call these components colors, in hearing we call these components tones, in smelling we call them odours, and in eating we call them flavors.
As pointed out, taste is the yin component of a flavor and yang the qi portion. Thus a food or herb that has a strong taste is more yin and “thick” than a taste that is more neutral and more yang and “thin.” The consumption of overly rich foods in modern times thus makes sense that we see so many excess yin conditions of obesity and depression. The five tastes correspond to the five elements (sour, bitter, sweet, pungent, and salty) and the qi of an herb is classified as cold, hot, warm, or cool.
Looking at the anatomy and physiology of the spleen through this five elemental lens yields some interesting findings. Primarily, the location of the spleen and its subsequent shape itself is dictated by physical contact with the stomach, the left kidney, and the diaphragm (lungs). The connections are obvious: physical contact entails that when one enlarges, the other must retreat and give-way. The laterally adjacent stomach and spleen (connected via the gastrosplenic ligament) balance each other energetically, the former descending and the latter ascending as if on a teeter-totter. The spleen also allows the lung to breathe (the generating cycle of Earth to Metal). An engorged spleen (Splenomegaly) would impinge on this area. So too would an enlarged spleen effect the left kidney (an interesting expression of Earth controlling Water).
The Spleen, containing the largest collection of lymphoid tissue in the body therefore makes good sense that it would be the clock pair of the Triple Warmer (sometimes thought to be the lymphatic system in general or the Extra-Cellular Matrix or connective tissue). As a holder of lymph and blood (30-40% of the bodies total platelet count), the Spleen blends the yin (blood) and yang (lymph) to clean and mount attacks. In this way, the Spleen can be seen as raising the clear freshly cleaned blood and lymph back into circulation. Splenectomies usually result in increased susceptibility to bacterial infection due to this lack of clearing ability.
In other pathologies such as congestive splenomegaly, the venous return system of the spleen becomes clogged. Interestingly, this usually only occurs in patients who already have liver cirrhosis. Because of the congested venous return, the heart begins to back-up and have experience its own problems. This is clearly a case of Wood invading Earth, a “wicked evil”, giving rise to the “Excess Evil” of Earth reversely controlling Fire. In a particular patient with congestive splenomegaly and liver cirrhosis, if the initiating factor is in fact determined to be liver excess the causative situation could be this “wicked evil.” These evils arise and are treated from the control cycle. When Wood over-controls Earth, the method is to tonify the controller of Wood, or Metal. This is done with pungent herbs such as Gui Zhi (cinnamon twig) and Fu Zi (aconite).
Another example of a Spleen pathology is a Splenic Infarct, which is essentially a lesion caused by an embolism originating from the circulatory system. In this case we can apply the 5 elemental understanding of physiology to see that Fire is influencing Earth in this case. With just the diagnosis of Splenic Infarct it is difficult to know if this is due to a deficiency or excessive condition. The former would be treated as a “Deficiency Evil” and the latter as a “Proper Evil.” Luckily, the treatments are identical in flavor. To treat deficiency, the Fire element, or Heart, would be treated by tonifying the Water element by using the bitter flavor. In the case of Proper Evils, we would support that organ with its corresponding flavor; in this case, the heart with bitter.
These are just two examples where a modern diagnosis can be explained and treated from the ancient methods of Chinese Medicine.