In Chinese medicine the Small Intestine takes what the Stomach has broken down and sorts it, sending the useful part on and the rest downward. It is paired with the Heart, belongs to the Fire element, and its channel runs up the back of the arm and across the shoulder blade.
We capitalize Small Intestine when we mean the Chinese medicine system and use lowercase for the anatomical organ. The functional overlap is reasonable, since both are doing a kind of sorting. What is different is the company it keeps. Chinese medicine pairs it with the Heart, and the classical explanation for that is that clear judgment and clear separation are the same skill applied to different material.
On this page. At a glance · What it does · The meridian · Common patterns · Herbs · Questions
At a glance
The Small Intestine is the yang organ of the Fire element, paired with the Heart. In the twelve channel cycle it comes sixth, immediately after the Heart.
| Chinese name | 小腸 (Xiǎo Cháng) |
| Element | Fire |
| Yin or yang | Yang (fu) |
| Paired organ | Heart (Xīn) |
| Season | Summer |
| Color | Red |
| Climate | Heat |
| Flavor | Bitter |
| Emotion | Joy, shared with the Heart |
| Opens into | The tongue, shared with the Heart |
| Governs | Separating the useful from the rest |
| Qi moves | Downward and outward |
| Peak hours | 1 to 3 p.m. |
| Meridian | Hand Taiyang, 19 points (SI1 to SI19) |
What does the Small Intestine do?
It separates. This is the whole job and the classical phrase for it is separating the clear from the turbid. What the Stomach sends down arrives here, and the Small Intestine decides what goes on to the Spleen to be made into qi and blood, what goes to the Large Intestine, and what goes to the Bladder. Three destinations out of one arrival.
It works for the Heart. The pairing looks odd until you read the classical description of it. The Heart is credited with clarity of mind and the Small Intestine with clarity of sorting, and the texts treat those as the same function on two different levels. Heat in the Heart is classically described as passing down to the Small Intestine, which is one of the more concrete examples of how the paired organs are understood to interact.
It shares the Taiyang with the Bladder. Together they make up the outermost of the six levels. That is why the Small Intestine channel across the shoulder blade gets used for stiffness and tension in the upper back, alongside the Bladder channel.
The Small Intestine meridian
The channel begins at SI1, at the outer corner of the little fingernail. It runs up the outer edge of the hand and along the back of the forearm on the little finger side, past the point of the elbow, and up the back of the upper arm.
It then does something no other channel does. Across the shoulder blade it zigzags, tracking the edges of the bone rather than running straight, which is why the points there are so often used for the upper back. From the shoulder it goes up the side of the neck and the cheek and ends at SI19, just in front of the ear.
Nineteen points.
Where it falls in the organ clock
| Hours | Organ |
|---|---|
| 11 a.m. to 1 p.m. | Heart |
| 1 to 3 p.m. | Small Intestine |
| 3 to 5 p.m. | Bladder |
The Small Intestine hour sits directly after the Heart hour and directly after most people eat, which is the traditional reading of the early afternoon.
Common Small Intestine patterns
These are traditional pattern descriptions, not diagnoses. Working out a pattern is a practitioner's job.
| Pattern | Traditional signs |
|---|---|
| Heat passing from the Heart to the Small Intestine | Restlessness, a red tip on the tongue, scanty dark urine, a sensation of heat |
| Small Intestine deficient and cold | Discomfort below the navel eased by warmth and pressure, loose stool, a pale tongue |
| Small Intestine qi not moving | A pulling or gripping sensation in the lower abdomen, worse with cold, relief with warmth |
Herbs traditionally associated with the Small Intestine
Very few herbs are described as entering the Small Intestine specifically. Most of what is used here works through the Heart, the Bladder or the Spleen instead, which is a fair reflection of how the organ sits in the system.
| Product | Traditional description |
|---|---|
| Dianthus Formula (Ba Zheng San Tang) | Traditionally used where the texts describe heat moving down into the lower body, which is the classical route from the Heart through this organ. |
One row, and the honest position is that this organ is reached through its neighbours. The page links to the Heart, the Bladder and the Spleen for that reason.
Questions people ask
Where does the Small Intestine meridian run? It starts at the outer corner of the little fingernail, runs up the outer edge of the hand and the back of the forearm, past the elbow, up the back of the upper arm, zigzags across the shoulder blade, then up the neck and cheek to end just in front of the ear. Nineteen points.
Which organ is paired with the Small Intestine? The Heart. They are the yang and yin organs of the primary Fire pair and share the same associations, which are summer, red, heat, the bitter flavor, and the tongue.
Why is the Small Intestine paired with the Heart? Because Chinese medicine reads both as doing a kind of sorting. The Heart sorts thought and the Small Intestine sorts what has been eaten. The texts also describe heat in the Heart as passing down into this organ.
What does separating the clear from the turbid mean? It is the classical description of the Small Intestine's job. What arrives from the Stomach gets divided three ways, with the useful part going on to the Spleen and the rest going to the Large Intestine and the Bladder.
What is the Taiyang? It is the outermost of the six levels in the classical framework, made up of the Small Intestine and Bladder channels. It is where the texts say something arriving from outside first reaches the body.