What Xuehai does
Xuehai sits above the inner knee, and its name means Sea of Blood. In skin practice it is used for Blood that is too hot, or Blood that has stopped moving, and often for both at once.
Actions
- Cools the Blood
- Invigorates the Blood and removes stagnation
- Nourishes the Blood when tonified
- Benefits the skin
- Regulates menstruation
Location
With the knee bent, two cun above the upper inner border of the kneecap, in a soft depression on the vastus medialis muscle.
How to find it
Bend the knee and find the upper inner corner of the kneecap. Measure two cun upward along the inner thigh and feel for a soft hollow in the muscle. It is usually slightly tender; the depression rather than the exact measurement is the better guide.
Deqi
Local distension and soreness in the muscle, sometimes spreading down toward the knee or across the inner thigh, often with a heavy, spreading warmth.
A cun is a proportional body measurement, not a fixed length: one cun is about the width of the thumb at the knuckle, 1.5 cun about two finger widths, and 3 cun about the width of four fingers. On an average adult one cun is roughly one inch, but it scales with the person, which is why the texts measure in cun rather than centimetres.
Technique
Needling
Angle: 90 degrees (perpendicular) Depth: 1.0 to 1.5 cun Direction: Vertically or obliquely 1 to 1.5 cun
Moxibustion
Five to ten minutes, used for cold in the Blood or stasis rather than for acute Blood-Heat.
Cupping
Used over the surrounding thigh for stasis and longstanding patches.
Gua sha
Gua sha along the inner thigh for stasis.
Bleeding
Bloodletting near the point is used for very hot, congested skin in practitioner settings.
Skin uses
- Eczema with redness and intense itch
- Herpes zoster pain
- Genital itching and related skin irritation
Point classifications
| Classification | Value |
|---|---|
| Name meaning | Sea of Blood (xue = blood, hai = sea) |
| Channel | Spleen, Foot Taiyin |
| Main skin role | Cools and moves Blood; the Blood-Heat point |
Classical record
The Blood sea is located on the inner thigh above the kneecap, two and a half cun above the white flesh border, and governs leaking discharge, blood blockage and rebellious Qi with abdominal distension.
Zhen Jiu Jia Yi Jing (针灸甲乙经, Systematic Classic of Acupuncture and Moxibustion). Later texts settle the location at two cun.
Safety
Who should treat this point
Acupuncture and bloodletting are practitioner procedures; this page is educational.
Caution
Use care in patients with a thin, weak pulse: the point strongly moves Blood and can further deplete someone who is already Blood deficient. In Blood deficiency, use tonifying technique only. In pregnancy, keep stimulation gentle because the point influences menstrual flow and uterine blood.
Deficiency and constitution
This is the main technique decision at Xuehai. Reducing suits hot, red, itchy skin; tonifying suits dry, pale, thin skin. Getting it the wrong way round makes the patient worse.
Before treatment
Educational reference only. A rapidly spreading hot red rash with fever needs medical assessment.
Modern evidence and safety
General references for acupuncture safety and skin evidence. They are not specific to this point, and they are not a claim that needling it treats any condition.
- Acupuncture-related adverse events: systematic review and meta-analyses of prospective clinical studies. BMJ Open, 2021. PMID: 34489268.
- Acupuncture for atopic dermatitis: a systematic review and meta-analysis. BMJ Open, 2024. PMID: 39638592.
- Manual acupuncture for the treatment of chronic spontaneous urticaria: a systematic review and meta-analysis. International Journal of Surgery, 2025. PMID: 40696933.
- Acupuncture in Dermatology: An Update to a Systematic Review. Journal of Alternative and Complementary Medicine, 2021. PMID: 32955916.
Evidence note
No controlled trial of this treatment in skin conditions was identified for this entry. What is described here rests on the classical and later materia medica record and on traditional clinical use, not on controlled trial evidence, and it is not a prediction of benefit. Where skin-specific research does exist it is linked above.
Common questions
Why is it called Sea of Blood?
Because it is the point where the Spleen channel's influence on Blood is strongest: it both cools Blood that is too hot and moves Blood that has stagnated.
Is it used for dry skin too?
Yes, but tonified rather than reduced. The same point nourishes Blood when the technique is tonifying.
Why pair it with Quchi?
Quchi clears the Heat and Xuehai cools the Blood beneath it, so the two work on the same problem from different levels.