Invasion of External Pathogenic Factors
These can be Cold, Dampness and Summer-Heat.
Cold can invade the Intestines directly bypassing the body's Defensive-Qi portion. This happens
when one is exposed to cold weather. Contrary to what one might expect, it happens more
frequently in summertime when one is lightly dressed. If there is a spell of unseasonably cold
weather, or if one stands in the wind after swimming with the body still wet, then Cold may
invade the Intestines and cause diarrhoea and abdominal pain. The "Simple Questions" in
chapter 39 says: "When Cold invades the Small Intestine, this cannot transform [food] properly
and diarrhoea and abdominal pain result."1(398) The "Spiritual Axis" in chapter 29 says:
When Cold invades the Stomach there is abdominal pain and distension; when it
invades the Intestines diarrhoea and borborygmi result. When the Stomach has
Cold but the Intestines Heat, then distension and diarrhoea result.2(399)Summer-Heat also invades Intestines and Spleen and is a frequent cause of acute diarrhoea in
summertime. In this case, the person will also have symptoms of invasion of the Defensive-Qi
system by Summer-Heat, i.e. fever and aversion to cold. The "Simple Questions" in chapter 5
says: "When Wind injures the body in Springtime, diarrhoea results in summertime".3(400)
Of the external pathogenic factors, Dampness is the one that most frequently causes diarrhoea.
External Dampness penetrates the channels of the leg and flows up to the Spleen where it
obstructs its function of transformation and transportation leading to diarrhoea.
Irregular Diet
Diet is of course a frequent cause of acute or chronic diarrhoea. The most common cause of
acute diarrhoea is eating spoiled food, too hot or too cold foods.
Chronic diarrhoea may be caused simply by over-eating or by the excessive consumption of
cold, greasy or sweet foods. These impair the transforming and transporting of the Spleen, so
that Spleen-Qi cannot ascend and diarrhoea results.
Zhang Jing Yue says in the "Complete Book of Jing Yue" (1634): "Diarrhoea is either due to
diet or invasion of a pathogenic factor ... when due to diet, there is Cold-Accumulation".4(401)
Emotional Stress
Worry, pensiveness, brooding and excessive mental work weaken the Spleen and may cause
chronic diarrhoea. Anger, which normally affects the Liver, may also affect the Spleen when one