While diseases weren't mentioned in the Nei Ching, there were definitely several references to breathing disorders. One such example can be found in chapter 34, or final chapter of the document. The discussion between Ti and Pai went like this:
The Yellow Emperor said: " Man is afflicted when he cannot rest and when his breathing has a sound (is noisy) -- or when he cannot rest and his breathing is without any sound. He may rise and rest (his habits of life may be) as of old and his breathing is noisy; he may have his rest and his exercise and his breathing is troubled (wheezing, panting); or he may not get any rest and be unable to walk about and his breathing is troubled. There are those who do not get a rest and those who rest and yet have troubled breathing. is all this caused by the viscera? I desire to hear about their causes."
Ch'i Po answered: "Those who do not rest and whose breathing is noisy have disorders in the region of Yang Ming (the 'sunlight'). The Yang of the foot in descending causes the present disturbance and is ascending it causes the breathing to be noisy. The pulse of the stomach is located in the region of the 'sunlight'. The stomach is the ocean of the five viscera. If the breath (of the stomach) does not function there is a disorder in (the region of) the 'sunlight' and it cannot follow its course; the consequence is inability to rest. In ancient classics it is said: 'If there is no harmony within the stomach, there is no peace (contentment, comfort, ease.
"Hence if the habits of life are as usual and the breathing is noisy, then the veins of the lungs are in disorder. The vessels are not in harmony with the main vessels which ascend and descend. Hence the main vessels are restrained and cannot function, and the man suffers from a disease of the veins.
"If, however, the habits of life are as usual and breathing is noisy; and if one cannot rest, or if one rests there is troubled breathing, then something has temporary residence in the breath; water follows the saliva and moves. The water of the kidneys influences the saliva, disturbs the rest, and causes the troubled breathing."
The Emperor said: "Excellent!"Now if that's not a line a B.S. I don't know what is, but hence was the theory of medicine in Ancient China, and it was based on this that breathing disorders, like asthma, were diagnosed and treated. To the health experts living at the time this explanation was completely rational.
For more on the Nei Ching and asthma in Ancient China, click here.
- Veith, Ilza, "The Yellow Emperor's Classic of Internal Medicine," Los Angeles, 2002, page 252-3 (Veith wrote the introduction and translated for us the Nei Ching as written by Huang Ti, the Yellow Emperor.)