Objective: Acupuncture, practiced for over 2000 years in Asia, stimulates specific but poorly defined sites called acupuncture points or acupoints. Until now, no unique anatomical structures of acupoint have been found. Noxious sensory signals from visceral organs produce highly localized hypersensitive spots on the skin (neurogenic spots), caused by cutaneous neurogenic inflammation, in the dermatome that overlaps with visceral afferent innervation. Results: The present study provides experimental evidence that neurogenic spots exhibit all the characteristics of the acupoints listed above. The stimulation of neurogenic spots by electrical, mechanical, or chemical means alleviated colitis and hypertension in rats. Conclusion: We demonstrate that acupoint is a localized form of neurogenic inflammation occurring on the skin associated with visceral disorders. The present study not only uncovers the identity of acupoint that is an old mystery in biology, but also reveals a novel role for skin neurogenic spots in treatment of visceral disorders.