在人體正常的生理機轉中，「渴」常被視爲一種正常訊息，而非負向的聯想。然而，血液透析息者因灌注到腎臟的血流減少，產生一連串生理的變化，使患者產生諸多的「致渴因子」。這些生理的變化包括血鈉升高、血糖增加、Angiotensin Ⅱ及唾液分泌不足等，同時也有一些與生理機轉無關的因素會影響個體的口渴感受。因此，「渴」對於血液透析患者而言是一種經常存在的現象。本篇文章藉由生理機轉的觀點，探討造成及影響血液透析患者口渴的因素，期使臨床專業照護人員能了解此類患者渴的現象，並進一步提供減輕口渴不適的相關措施，以提升血液透析患者的照護品質。

Thirst is a normal physiological response of human body. However, several biochemical and physiological abnormalities, including renin-angiotensine-aldosterone system, hypernatremia, hyperglycemia, and lower salivary flow rate have been reported to involve in the thirst mechanism of End Stage Renal Disease (ESRD) patients. Therefore, thirst is one of the most common problems found in hemodialysis patients. The purpose of this article was to discuss physiological mechanism of thirst in hemodialysis patients. The article aims to assist nursing staff developing intervention strategies to decrease thirst perception of ESRD patients and improve the quality of care.