「食忌」是中國醫學中相當具有特色的一環，其源頭可以追溯至上古時代。隨著時代的推移，對於許多疾病，人們都逐漸發展出特定的飲食禁忌。本文以秦漢時期的「熱病」爲中心，來探討當時食忌知識所經歷的變化：由日常生活之養生勸訓轉而成爲醫學理論的重大轉變。以熱病來說，它本身就包含了今天所謂的數種傳染病，在古代的疾病譜系中是一種統稱與歸類，形成一套相當龐雜的體系。因此，從熱病豐富的內涵出發，審視其發病之症狀與調養、禁忌之連結，有助於我們認識食忌知識的成形。醭清這些食忌知識在秦漢醫療發展史中的定位與歸屬，是本文最重要的課題。 本文設想，「飲食致病」的思維建構，除了根據實際經驗的累積外，同時應有理論架構的指導方才臻於完整。經過初步探討，本文指出秦漢之際的食忌理論發展有三個相互重疊、互相影響的層次：第一階段是依附於養生類文獻內，其後則逐漸依據醫療經典的理論來歸類，而漸漸具有系統，最後才是個別疾病之食物禁忌、服藥與本草的禁忌譜系成形。此三層演變有時間先後，且互相滲入；在定型之後，又一起存在於醫療與社會文化中，而各具特色。它們具有的意義，不單是醫療的概念而已，尚且隱含了中國人對疾病與飲食關係的認知與約定成俗的身體觀。

Developed since high antiquity, the concept of 'dietary prohibition' has had a special place in Chinese medicine. Gradually throughout history, most diseases developed their corresponding dietary prohibitions. By studying 'feverish disease,' a category of disease that was widespread in the Ch’in and Han dynasties, this article discusses the evolution of the concept of dietary prohibitions: how the concept was transformed from persuasions and dissuasions for keeping in good health to become a medical theory. 'Feverish disease' is a category that actually includes various contagious diseases now classified and separately named. In ancient times, diseases were classified and generally known only as a single disease in the typology of diseases, which consequently formed a huge and jumbled system for classifying diseases. Therefore, examining the symptoms of feverish disease and the connection between treatment and dietary prohibitions will help us understand how knowledge on dietary prohibitions was developed and accumulated. Clarifying the orientation of knowledge about dietary prohibitions in the history of Chinese medicine in the Ch'in and Han dynasties is the most important aspect of this article. In this article, it is assumed that the development of knowledge about dietary prohibitions was built upon experience and guided by a theoretical construct. Our preliminary study shows that the theory of dietary prohibitions in the Ch'in and Han dynasties can be categorized into three overlapping and interlinking phases. At first the notion of dietary prohibitions was recorded in the documents on keeping in good health. As time went on, each prohibition was categorized by medical theory and thus the knowledge construct became systematic. Finally, each disease developed its corresponding dietary restriction, remedy and materia medica, which then forms a pedigree of prohibition. These three interpenetrating but distinguishable phases evolve one after another and co-exist in the medical treatment and social culture. We can say that the notion of dietary prohibitions not only represents a distinct concept in medical treatment, but shows by implication the ideas that the Chinese people held on the relationship between diet and disease and the observations that Chinese people made about the body through everyday practice.