RESUMEN
Needle retention is an important step in the acupuncture procedure. How to optimize scientifically the duration of needle retention according to individual case has been considered in the medical circle. In this paper, by collecting the literatures on needle retention from the early dynasty to the contemporary time, the evolution of the needle retention from a short duration to a long one with the productivity improvement was elaborated. On the base of the views of the medical scholars of all dynasties, it was concluded that the ultimate purpose of needle retention is to improve the effects of acupuncture on the premise of ensuring the safety of acupuncture. Hence, the clinical physician should optimize the duration of needle retention cautiously in compliance with the tolerance of patient so as to save the time cost of both physician and patient, avoid the occurrence of tolerable effect of acupuncture and reduce the potential safety hazard of acupuncture induced by the long duration of needle retention.