Large intestine

Large Intestine Functions

The Large Intestine Governs Conveyance and Transformation of Waste (大肠主传化糟粕 dà cháng chuán huà zāo pò)

The contents of the small intestine are passed on to the large intestine. Here, they are transformed into stool. Thus, the large intestine is said to govern the conveyance and transformation of waste. Conveyance refers to the large intestine’s function of carrying waste matter downward and expelling it through the anus. The transformation of waste refers to the removal of excess liquid from the solid matter. This function is described in the Sù Wèn (Chapter 8) as follows: The large intestine holds the office of Conveyance; mutation arises from it (大肠者, 传导之官也, 变化出焉 dà cháng zhě, chuán dǎo zhī guān yě, biàn huà chū yān).

Disturbance of large intestine function can give rise either to diarrhea, sometimes with ungratifying defecation, to tenesmus, or to constipation.

The Large Intestine Governs Liquid (大肠主津 dà cháng zhǔ jīn)

Water is needed to keep the contents of the digestive tract flowing. The large intestine is the final section of the digestive tract, and here excess fluid is drawn off so that the waste can be reduced to relatively solid feces. The large intestine’s absorption of fluid helps to regulate water metabolism. Hence, it is said that the large intestine governs liquid.

If the large intestine fails to absorb liquid, rumbling intestines, abdominal pain or diarrhea can result. Repletion heat scorching fluids or depletion of large intestine liquid can cause constipation.

The Large Intestine Channel (大肠经 dà cháng jīng)

The channel associated with the large intestine is the hand yáng brightness (yáng míng) large intestine channel (LI).

Large Intestine Signs and Patterns

For fuller information than is given below, follow the pattern links. See large intestine pattern identification.

Large intestine conditions are mostly characterized by either diarrhea or constipation, although these are, though less commonly, also associated with the spleen. Large intestinal diarrhea due to damp-heat is associated with several specific signs.

Diarrhea is increased frequency of defecation as well as the increased fluidity of sloppy stool that is typically associated with spleen qì vacuity. Diarrhea is the main feature of large intestine vacuity cold, where in severe cases it can culminate in prolapse of the rectum. It is also a main feature of large intestine damp-heat where it may be accompanied by ungratifying defecation, tenesmus, and pus (mucus) and/or blood in the stool.

Constipation is a marked reduction in frequency by comparison with the patient’s normal bowel habits (which can vary from twice a day to once in two days), and hence is defined by failure to defecate for 3–4 days or more. Constipation is a feature of large intestine liquid depletion (a vacuity pattern) and of intestinal heat bowel repletion (a repletion pattern).

Intestinal heat bowel repletion (肠热腑证 cháng rè fǔ zhèng): This pattern occurs in externally contracted febrile disease. It is marked by high fever peaking in the afternoon (late afternoon tidal heat effusion), profuse sweating, thirst, distension, fullness, hardness and pain in the umbilical region that refuses pressure, constipation, fetid stool, short voidings of yellow urine, clouded spirit, and delirious speech. The tongue is red with a dry, thick, yellow fur or parched black with prickles. The pulse is sunken and rapid (or slow) and forceful.

Large intestine damp-heat (大肠湿热 dà cháng shī rè): Abdominal pain, ungratifying defecation, tenesmus, scorching heat in the anus, fulminant diarrhea (sudden and violent diarrhea) with fetid yellow stool, short voidings of reddish urine, thirst, and in some cases heat effusion. Sometimes, there is diarrhea with stool containing blood (red) and pus (white), indicating dysentery. The tongue is red with a slimy yellow fur. The pulse is soggy and rapid or slippery and rapid.

Large intestine vacuity cold (大肠虚寒 dà cháng xū hán): Debilitation of the yáng qì of the large intestine manifesting in reduced removal of fluid from the waste and in impaired retention. It results from persistent diarrhea or dysentery or from inappropriate treatment. It manifests in diarrhea with fecal incontinence or even prolapse of the rectum. Other signs include dull abdominal pain that likes warmth and pressure; fear of cold and cold limbs; lassitude of spirit and lack of strength; pale tongue with glossy white fur; a pulse that is sunken and weak.

Large intestine liquid depletion (大肠液亏 dà cháng yè kuī): Also called intestinal dryness and liquid depletion. The signs are constipation with dry bound stool that is difficult to evacuate, dry pharynx, dry mouth, fetid mouth odor, and dizzy head. The tongue is red with scant liquid. The pulse is fine and rough.