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Examining the nature of all things, there are always principles of attraction and repulsion. When a tiger roars, wind arises; when a dragon chants, clouds gather. Magnetite attracts iron needles; amber gathers mustard seeds. Lacquer disperses upon contact with crabs; hemp swells or reacts upon contact with lacquer; Cinnamon Twig (Guizhi) becomes soft when combined with Scallion White (Congbai); trees wither when exposed to Cinnamon Twig; Rock Salt (Rongyan) can be piled like eggs; otter gallbladder bile can divide a cup of wine in two. Their qi interacts and influences each other, mostly in such categories; the underlying principles are difficult to fully comprehend through thought alone. Regarding various medicinal substances, they particularly influence each other's efficacy and harm. The ancient sages have clearly expounded on this theory; how can one fail to examine it in detail and avoid these interactions? Contemporary practitioners compiling prescriptions often omit or overlook these details. If an existing prescription contains such combinations for a specific condition, those incompatible pairings should be modified or removed. If two substances have comparable properties, based on the severity of the illness, one should choose to remove the less suitable one. In the Chisan Decoction (Chisan San) for Cold Damage (Shanghan), I frequently omit Veratrum Rhizome (Lilü). In the Coptis Pill (Huanglian Wan) for dysentery, I also remove Ginger Tuber (Ganjiang) before administering it, achieving consistent efficacy. Why insist on forcing mutually antagonistic substances together, merely allowing them to coexist? The harm caused by "incompatibility" (Xiangfan) is far more severe than that of "mutual aversion" (Xiang'e). "Mutual aversion" means that although substance A dislikes substance B, substance B does not harbor resentment towards A. For instance, Realgar (Niuhuang) is averse to Dragon Bone (Longgu), yet Dragon Bone achieves better efficacy when combined with Realgar, because they mutually restrain each other's toxicity or side effects. "Incompatibility," however, implies that the two substances are like enemies and must not be combined. Modern painters note that when Orpiment (Yinghuang/Cihuang) and Lead White (Hufen) are placed near each other, they dull and "jealously" affect each other. Powder turns black when mixed with Orpiment, and Orpiment changes color when mixed with powder; this serves as evidence of incompatibility. Because pharmacological principles are misunderstood, treatments often fail, leading people to disregard them. Now, regarding prescription formulation, it may not be possible to immediately consult the Materia Medica thoroughly. Therefore, I have copied these relevant cases here for reference. A brief review will make verification easy. Furthermore, the *Shennong Bencao Jing* simply lists "Cornus" (Zhuyu) and "Asparagus Root" (Mendong) without distinguishing between Mountain Cornus (Shanzhuyu) and Wujiapi (Wu Zhuyu), or Asparagus Root (Tianmendong) and Wheat Root (Maimendong). All such entries should specify the variety. There are instances of confusion, such as Sea Clam Shell (Haige) and Clam Shell (Bie Jia), which share identical mutual aversions. Additionally, various Ganoderma species enhance the efficacy of Yam (Shuyao), while Yam enhances the efficacy of Purple Ganoderma (Zizhi). It is unlikely that this reciprocal enhancement is correct, but it is unclear which is right or wrong. These should be recorded together for future comprehensive verification and correction. Moreover, in the *Shennong Bencao Jing*, the principle of "mutual enhancement" (Xiangshi) lists only one partner per herb. Cross-referencing with the *Yaodui* reveals two or three partners for some herbs, which poses no objection. Entries stating that substances "mutually accord" (Xiangde) to treat specific diseases are not listed here, as they do not fall under the prohibitions of avoidance or incompatibility.