《尔雅·释虫》∶ 、白鱼。郭璞注∶今衣书中虫，一名 鱼，《别录》及《图经》、《千
金翼方》，亦同。《千金方》、《外台秘要》，或曰衣中白鱼，或曰书中白鱼，又单称白鱼。虽
然，《本经》未尝以白鱼为本名，则古方所谓白鱼者，是必鱼部白鱼，非衣书中白鱼矣。况
又虫而得鱼名者，以其形稍似鱼，其尾又分二歧，故得 及 鱼、蠹鱼之名。虽然，但不可
单以白鱼为本称也。后之用此者，能治小便不利，则益以衣中白鱼为古方白鱼矣。滑石白鱼
散证曰∶小便不利。此方本载于《金匮要略》小便利淋篇内，则盖淋家小便不利者主之。本
草∶衣鱼，主治小便不利。《别录》疗淋，附方又载此方，主治小便不通。然则诸家皆以衣
鱼为白鱼，明矣。虽然，此方内白鱼，未可知衣中白鱼否，并存此二物，以俟后之考订试效。
凡药方内，有不以本名称，而以异名呼之者，不欲使人知其物也，是皆后世医家之陋也。
独仲景之方，无以异名称之者，如彼乌头、附子、天雄，则以其年数形状称之；如彼芒硝、
硝石、朴硝。则以其制之精粗，功之缓急取之；如彼白 酒、浆水，则以诸家所称之名呼之，
或以诸家所传之方录之，盖无异义。按仲景撰用诸家之方，未尝变其方名，根据其所称而取之
耳。然则如此白鱼散，当须根据其本名矣。由是观之，白鱼者，盖非衣中白鱼明矣。明者其审
诸。
《尔雅·释虫》记载：“䖪，白鱼。”郭璞注释说：就是现在衣服书籍中的虫子，又名䖪鱼，《名医别录》及《本草图经》、《千金翼方》也都这样认为。《千金方》、《外台秘要》，有的称为衣中白鱼，有的称为书中白鱼，又单称为白鱼。虽然如此，《神农本草经》从未以“白鱼”作为本名，那么古方中所说的“白鱼”，必定是鱼类中的白鱼，而不是衣服书籍中的白鱼。况且昆虫却得到鱼的名字，是因为它的形状稍微像鱼，尾巴又分为两个叉，所以得到䖪及䖪鱼、蠹鱼（书虫）的名称。虽然如此，但不可单独以“白鱼”作为它的正式名称。后来使用这种药的人，能够治疗小便不利，于是更加认定衣中白鱼就是古方中的白鱼了。滑石白鱼散的证候说：小便不利。这个方子原本记载在《金匮要略》小便利淋篇内，则是大概主治淋家（患淋病的人）小便不利的。本草记载：衣鱼，主治小便不利。《名医别录》治疗淋病，附方又记载此方，主治小便不通。既然这样，各家都以为衣鱼就是白鱼，这是很明显的了。虽然如此，这个方子里的白鱼，不知道是不是衣中白鱼，暂且将这两种东西并存，以等待后人的考证和试用验证。
凡是药方里面，有不使用本名而用异名称呼的，是不想让人知道是什么药物，这都是后世医家的陋习。唯独张仲景的方子，没有用异名称呼的，比如那些乌头、附子、天雄，就按照它们的年份和形状来称呼；比如那些芒硝、硝石、朴硝，就按照炮制的精粗、功效的缓急来选取；比如那些白酒、浆水，就用各家所称的名称来称呼，或者用各家所传的方子来记录，大概没有其他的含义。考察张仲景撰写时采用的各家方子，从未改变其方名，只是根据它们所称的名称来选取罢了。既然这样，那么像这样的白鱼散，应当必须根据其本名来确定。由此看来，白鱼，大概不是衣中白鱼，这是很明显的了。明白的人请仔细审察。
*Er Ya · Shi Chong* records: "Jue, Bai Yu (White Fish)." Guo Pu commented: "It is the insect found in clothes and books today, also named Jue Yu. *Bie Lu* (Additional Records of Materia Medica), *Tu Jing* (Illustrated Classic of Materia Medica), and *Qianjin Yi Fang* (Supplement to Essential Prescriptions Worth a Thousand Gold) all agree." In *Qianjin Fang* (Essential Prescriptions Worth a Thousand Gold) and *Waitai Miyao* (Secret Essentials of the Outer Cabinet), it is sometimes called "Yi Zhong Bai Yu" (White Fish in Clothes), sometimes "Shu Zhong Bai Yu" (White Fish in Books), or simply "Bai Yu" (White Fish). Nevertheless, *Ben Jing* (Shennong's Classic of Materia Medica) never used "Bai Yu" as its primary name. Therefore, the "Bai Yu" mentioned in ancient prescriptions must refer to the White Fish from the fish family, not the White Fish found in clothes and books. Moreover, insects that bear the name of fish do so because their shape somewhat resembles a fish, and their tails are bifurcated; thus, they are named Jue, Jue Yu, and Du Yu (Bookworm). Even so, one cannot use "Bai Yu" alone as its formal name. Later users of this substance, noting its ability to treat difficult urination (Xiao Bian Bu Li), further identified the Yi Zhong Bai Yu as the Bai Yu of ancient prescriptions. The indications for Huashi Bai Yu San (Talcum, White Fish, and Lygodium Spores Powder) state: "Difficult urination." This prescription was originally recorded in the chapter on Normal Urination and Stranguria in *Jin Gui Yao Lue* (Essential Prescriptions of the Golden Cabinet); thus, it is likely intended for patients with stranguria (Lin Jia) who suffer from difficult urination. Materia Medica records: "Yi Yu (Clothes Moth) treats difficult urination." *Bie Lu* states it treats stranguria, and the attached formulas record this prescription for treating complete inability to urinate. Consequently, various authorities have equated Yi Yu with Bai Yu, which is clear. However, regarding the "Bai Yu" in this formula, it is uncertain whether it refers to the Yi Zhong Bai Yu. Both substances are preserved here for future verification and efficacy testing.
In medicinal formulas, when a substance is referred to by an alias rather than its proper name, it is often to conceal its identity; this is a flaw of later physicians. Only the formulas of Zhang Zhongjing did not use aliases. For instance, Wu Tou (Aconite Root), Fu Zi (Prepared Aconite Root), and Tian Xiong (Lateral Root of Aconite) were named according to their age and shape; Mang Xiao (Mirabilite), Xiao Shi (Niter), and Pu Xiao (Saltpeter) were distinguished by the refinement of their processing and the urgency of their effects; Bai Jiu (White Wine) and Jiang Shui (Sour Rice Water) were referred to by the names used by various schools or recorded from transmitted formulas, without any hidden meaning. Examining the formulas Zhang Zhongjing adopted, he never altered their original names but selected them based on the names given by others. Therefore, for a formula such as Bai Yu San, one must determine the ingredient based on its proper name. From this perspective, it is evident that "Bai Yu" does not refer to the Yi Zhong Bai Yu. Those who understand this should examine it carefully.