Acupuncture syncope（commonly know as needle fainting），long considered an adverse event to be prevented，has been found to result in rapid recovery for almost all patients with appropriate management. Some patients even experience“significant”therapeutic effects after fainting. Though the mechanism of acupuncture syncope and its potential benefits have not been thoroughly investigated，this article，based on reviews of extensive literature on acupuncture syncope（case reports，surveys，and systematic reviews）and recent research on vasovagal syncope，supports the notion that acupuncture syncope is not harmful. It raises a novel point that acupuncture syncope is actually a form of vasovagal syncope rather than shock. The pathophysiological basis of acupuncture syncope includes patientsusceptibility to syncope，arterial baroreflex dysfunction or instability，and vasovagal responses triggered by psychological stress，postural stress，and particularly acupuncture（somatic nerve stimulation）. Based on its neurological mechanism，acupuncture syncope can be classified into three types. Type Ⅰ（psychological stress type）occurs immediately before and after the needle is inserted. Type Ⅱ（sympathetic triggering type）is further divided into progressive sympathetic activation type（Type Ⅱ a）and inhibitory type（Type Ⅱ b）. The sympathetic excitability of this type is initially high，which further increases under needle stimulation before suddenly or gradually decreasing，leading to fainting. Type Ⅲ（vagus-triggered type）is induced by directly stimulating vagalafferentatsome special parts of the body （e.g.，the auricular region）. The article proposes that the significant therapeutic effects experienced by some fainting patients（mainly Types Ⅱ and Ⅲ）are related to the strong stimulation of acupuncture and the fainting itself，which strongly activate the hypothalamic-pituitary-adrenal axis，cholinergic vagal anti-inflammation pathways，and reset disease homeostasis. For patients susceptible to syncope，clinicians should mitigate psychological stress and administer light acupuncture stimulation in the supine position when needed. When pre-syncope symptoms occur，preventing falls and should be the first priority. Unless syncope persists，additional needle insertion is unnecessary，though existing needles may be retained for the duration of treatment. For patients who have not responded to previous acupuncture treatments，clinicians might consider intentionally selecting more sensitive acupoints and applying more intensive stimulation at an orthostatic posture to induce syncope. This approach aims to achieve a more effective treatment outcome. In essence，clinical management should consider the trade off between ensuring patient safety and maximizing treatment efficacy.

acupuncture syncope  /  vasovagal syncope  /  neural mechanism  /  classification  /  adverse event  /  safety  /  efficacy  /  trade off