Nourish your physical form and do not dissipate your Jing (Essence), thus you can attain longevity. This statement is indeed an excellent method for the regulation and care of Xu Lao (Deficiency Consumption). I observe that among people in the world, six or seven out of ten suffer from Xu Lao (Deficiency Consumption); yet, among a hundred, it is rare to find one who remains healthy. This is because patients seek treatment too late, and physicians treat improperly. In my youth, I contracted this illness; after regulating and nourishing myself for over twenty years, I remain unharmed to this day. This demonstrates that this disease is certainly curable. However, whenever I discuss this condition, I feel deep pain and worry. Therefore, I specifically elucidate the causes leading to Yin Deficiency pathology, then address the chaotic categorization found in medical texts, further explore the reasons why True Yin is prone to deficiency, as well as the transmission and multiplication of symptoms regarding their root and branch aspects, and the detrimental effects of misdiagnosis and mistreatment. I begin with the essentials of treatment. The purport of this work is thus: I dare not merely correct the biases of the contemporary era, but rather aim to expound upon the experiences of ancient sages, which I have personally experienced and verified without error. Thus, I share my sincere thoughts, hoping that both physicians and patients will repeatedly reflect upon this chapter.