The back gateway to the Small Intestine. Xiaochangshu (BL-27) reaches directly to the organ that separates the pure from the impure — regulating the lower body, clearing Dampness and Heat from the intestines, and easing pain along the lumbar spine and sacrum.
Contraindications
BL-27 is a generally safe point when needled to the stated depth by a qualified practitioner. No special contraindications are noted in the sources.
Name & story
The name 小肠俞 Xiaochangshu tells its story simply and honestly: 小肠 (Xiǎocháng) means "Small Intestine", and 俞 (Shū) means a "transport" or "infusion" point — a place where the Qi of an organ is transported outward to the back. So the name simply says: "the back-Shu point of the Small Intestine". It is the point where the energy and condition of the Small Intestine surfaces on the back — where you can both read it and influence it. In Chinese medicine, this kind of point is treated as a direct window into the organ it names.
Point family & character
Xiaochangshu (BL-27) belongs to the Bladder Meridian (BL), which runs like a long river down the back and carries all the back-Shu points of the internal organs. BL-27 is the Back-Shu point of the Small Intestine — its most direct representative on the back of the body. Through this point, the Small Intestine's function of separating the clear from the turbid can be directly supported or regulated.
Five-element dynamics
The Small Intestine in Chinese medicine is a Yang organ paired with the Heart. Its great task is discernment — it receives the partially transformed food from the Stomach and separates what is pure and useful (sent upward to the Spleen) from what is turbid and waste (sent downward to the Large Intestine and Bladder). When this sorting fails, Dampness and Heat accumulate in the lower body, the urine becomes troubled, and the bowels lose their rhythm. Xiaochangshu (BL-27) works right at this junction — restoring the Small Intestine's power to distinguish, drain, and let go.
Location
Find the first sacral foramen on the back of the sacrum, 1.5 Cun lateral to the midline, at the level of the first sacral foramen (S1). It sits just below the fifth lumbar vertebra, on the same horizontal band as the upper part of the sacrum.
Anatomy & fascia
The point lies in the sacral region, over the posterior sacral foramina, in the area of the sacral musculature.
Needling
The needle is inserted perpendicularly, straight into the tissue.
Safe depth
The golden tip
For lower back and sacral aching, gentle self-massage or firm pressure with the thumbs over the sacral area — where BL-27 sits — can ease tension and improve local circulation. A warm pack placed across the sacrum is a simple and comforting home remedy, particularly helpful when the pain feels worse in the cold. Those familiar with moxa may gently warm this area to address cold-type abdominal or urinary discomfort.
For education only — not medical advice. Consult a qualified practitioner.