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The medical learning of Zhang Zhongjing underwent a significant transformation by the Tang Dynasty. In treating diseases, Zhang Zhongjing’s discussions on Zang-Fu organs (internal organs) and Jing-Luo meridians (meridian system), as well as the transmission and progression of conditions, were entirely based on the *Huangdi Neijing* (Yellow Emperor's Inner Canon). The formulas he used were all classical prescriptions (Jingfang) passed down from ancient sages, not created arbitrarily by personal whim; even when modifications were made, they were necessarily grounded in established principles. The dosages and weights of the herbs strictly adhered to specific standards. Every herb used was derived from the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), with no herb being used loosely or ambiguously. No formula could treat a specific disease other than its designated one, and no prescription could be formed without its specific herbs. Their subtlety and profound sophistication are beyond imagination. With merely five or six ingredients, their therapeutic effects were comprehensive. This reflects the transformative mechanism of Heaven and Earth, and the miraculous application of the sages, which is in harmony with nature and immortal.

The *Qianjin Fang* (Prescriptions Worth a Thousand Gold) is different. Although its discussion of diseases is not devoid of references to the *Huangdi Neijing*, it inevitably incorporates speculative theories from later generations. The formulas it employs are selected from ancient prescriptions but also include methods from later periods that are biased or eclectic. The herbs used are not solely based on the *Shennong Bencao Jing*; they also incorporate miscellaneous single prescriptions and general-purpose remedies. Consequently, there are instances where multiple formulas are established for a single disease, or one formula treats multiple diseases. Some prescriptions contain dozens of ingredients; while many are symptomatic, many others are not, resulting in variable efficacy—some treatments work, others do not. Generally, the emphasis lies heavily on the quantity of herbs, while the ancient sages' methodology for formulating prescriptions has been lost. This constitutes a major shift in the medical way. Nevertheless, its unique use of herbs and ingenious intent establish it as a distinct school with enduring value.

Wang Tao’s compilation in the Tang Dynasty, the *Waitai Miyao* (Essential Prescriptions from the Imperial Library), collected and compiled various prescriptions from the Han Dynasty onwards into a single volume, thereby preserving the prescriptions of successive dynasties comprehensively. However, Wang Tao was not a specialist in medical expertise; thus, he did not exercise rigorous selection to establish a clear guiding principle, making this work essentially a classified collection of medical formulas. Yet, because prescriptions prior to the Tang Dynasty were preserved through this book, its merits cannot be ignored. However, readers who lack a solid foundational understanding ("bamboo in mind") will find themselves confused by the conflicting theories and mixed prescriptions, losing their reference point. Therefore, those studying the *Qianjin Fang* and *Waitai Miyao* must first master the *Huangdi Neijing*, the works of Zhang Zhongjing, and the *Shennong Bencao Jing*. Only by having a firm preconception can one select the strengths and discard the weaknesses, thereby benefiting from their breadth and depth. Otherwise, one’s mind will be confused, leaving one at a loss. Alas! If the *Qianjin Fang* and *Waitai Miyao* are like this, how much more so are the biased, contradictory, and chaotic books of later generations, which inevitably bewilder the mind? Even worse are the baseless, fabricated heretical texts of lower quality, which are hardly worth mentioning.