Objectives : Dianji is a classic mental disorder in oriental medicine. Dian is often used as a name of disease together with Xian and Kuang. However, much confusion arises due to the usage of such words as Diankuang or Dianxian without the full comprehension of these terms' meanings. Dian, especially, is contained in both, so there is a need to clearly define its meaning. Therefore, the paper aims to study in what context Huangdineijing, the oldest classical medical text in oriental medicine, used Dian. Methods : All statements in Huangdineijing containing Dian were studied to create a number of categories. Based on this analysis, the paper attempted to understand Dianji's symptoms, mechanism, natures, and more. Then lastly, the relationship between the usage of Kuang and Xian was pondered upon. Conclusions & Results : The mechanism of pathology of the Dianji in Huangdineijing can be understood within the scope of upper excess and lower deficiency and the reversal of qi. Additionally, Dianji refers to a sickness in the head, and has a essence of spirit disease. Dian and Kuang were expressed as two types of relationship. One expression was a form of symptom that becomes visible during the occurrence phase of Dian, and the other expression was the cases where it was used as an independent sign. On the other hand, there was no case where Xian and Dian were explained in conjunction with each other. However, there still exist some similarities, mainly in that both diseases revolves aroundepilepsy.