When you sweat easily after eating hot food, or drinking hot beverages, it means your body’s Qi is not harmonized between the interior and the exterior. The body’s Yin is the stabilizing ability of our immunity, while its Yang is its defensive ability (including the ability to recognize antigens). They can be understood as two opposite forces. Yin is centripetal, while Yang is centrifugal. We produce abnormal sweats when our centripetal force (Yin) is weak while our centrifugal force (Yang) is strong.

When the Yin is unable to anchor Yang properly, Yang leaves the body, causing our immunity to be compromised. This explains why we get sick easily after being exposed to cold temperature.

The mechanism is explained in Huangdi Neijing, Lingshu (Yellow Emperor’s Inner Canon, Spiritual Pivot), Chapter 18 Nutritive and Defensive Qi – Locations of Generation and Meeting —

“When a person ingests hot food or hot drinks, he sweats before his Qi has settled, sometimes in the face, sometimes on the back, sometimes in the upper body. How come the sweat does not follow the passages of the Defensive Qi to emit from the body?

“Qibo replied: This is due to external Wind damage. The skin portals are forced to open from the interior. The body hair is steamed by the heat, which leak out from the grains of the skin. The Defensive Qi leaks out from these openings, therefore unable to follow their regular passages. This is because the [Defensive] Qi is powerful, slippery and rapid. It leaves the body from any openings. Hence it is unable to follow its regular passages. This is called Leakage Outflow.”

Any disease can happen when our immunity is compromised. A pathogen can enter the body, attack wherever there is weakness, stay inside our body for a long time, and transform into more serious diseases. Wind damage is considered the origin of hundred diseases for this reason.

This is why Gui Zhi Tang is the #1 formula in Shang Han Lun (Treatise of Cold Damage). It harmonizes the Yin (Nutritive/Interior) and the Yang (Defensive/Exterior) and allows our body to recognize and kill the pathogens before it sinks deeper into our tissues and transform into more severe diseases. It is important to ingest hot rice gruel, keep warm, and avoid strong-flavored food, meats, and alcohol after taking the formula because digesting such food takes a lot of the body’s resources.

In severe acute cases when a person shows signs of Yin damage (unstoppable sweating, aversion to wind, difficulty in urination, spasms and stiffness of the extremities) due to the Yang leakage, processed aconite (Fu Zi) and an extra portion of licorice root (Gan Cao) are added to restore the depleted Yang. (Shang Han Lun, Chapter Taiyang Disease, Line 19 “太陽病，發汗，遂漏不止，其人惡風，小便難，四肢微急，難以屈伸者，桂枝加附子湯主之。”) When Yang is restored, Yin will generate naturally on its own. This formula is unsuitable for chronic cases, in which the True Yin is damaged and cannot be replenished by tonifying Yang.