The Large Intestine receives water from the Small Intestine, reabsorbs some fluids and excretes
stools. Cold is obstructing and it may affect the Large Intestine by blocking its excretion of
stools. This causes constipation of the Cold type. In this case the stools are not dry.
Spleen
Although Spleen-Qi normally ascends and its pathology usually involves diarrhoea, deficient
Spleen-Qi may also cause constipation. It may do so because the movement of wastes and stools
in the Large Intestine relies on Spleen-Qi. Thus, if Spleen-Qi is deficient and it does not provide
enough Qi to move the stools in the bowel, constipation may ensue. In this case the stools may
be thin and long.
Liver
Liver-Qi ensures the smooth flow of Qi in every organ. In the Lower Burner, it ensures a smooth
movement of stools in the Large Intestine. If Liver-Qi stagnates, it causes stagnation of Qi in the
Lower Burner and the Large Intestine so that the stools are knotted and cannot move downwards.
In this case the stools are small and round like pebbles.
Kidneys
The Kidneys control the two lower orifices - urethra and anus - and they therefore influence
defaecation. Kidney-Yin deficiency involves deficiency of fluids: this affects the Large Intestine
as there are not enough fluids to moisten the stools which therefore cannot move smoothly
downwards. Wu Ju Tong (1758-1836) in his book "Differentiation of Warm Diseases" says:
"When fluids are deficient there is not enough water to make the boat move."3(409) "Boat" here
stands for stools. In this case the stools are dry.
Although Kidney-Yang deficiency will normally cause diarrhoea, it may also cause constipation.
This happens when Yang Qi in the Lower Burner is so deficient that it cannot move the stools.
On the other hand, Kidney-Yang deficiency over a long period of time will lead to Cold in the
Lower Burner which further obstructs the movement of the stools. In this case the stools are not
dry and defaecation is very difficult, succeeding only with great strain.
Thus, to summarize, constipation may be caused by:
- Heat
- Stagnation of Qi
- Deficiency (of Qi, Yang, Blood or Yin)
- Interior Cold.