Diarrhea refers to loose, water-like and frequent discharge of stool, usually due to improper diet, exogenous pathogenic factors, insufficiency of yang qi in the body and emotional disorders which lead to failure of the spleen to transform and failure of the small intestine to separate lucidity from turbidity, resulting in direct downward flow of water and failure of the large intestine to transmit. Generally speaking, acute diarrhea in new disease is usually of sthenia syndrome; slow diarrhea in prolonged disease is often asthenia syndrome. Diarrhea, marked by fulminant discharge, yellowish chyle, abdominal pain and scorching heat sensation of the anus, is usually due to internal accumulation of damp heat in the intestines; clear loose stool mingled with water and feces, accompanied by abdominal pain.

Borborygmus together with whitish greasy tongue fur, is caused by internal invasion of cold dampness which encumbers the spleen yang to separate lucidity from turbidity diarrhea following abdominal pain, marked by putrid and foul odor like decayed eggs, alleviation of pain after diarrhea and acid regurgitation is usually due to retention of food which damages the spleen and stomach and leads to failure of the intestines to transmit; loose stool following dry feces, accompanied by abdominal distension, reduced appetite, worsened distension after meal and lassitude, is often caused by asthenia of splenic qi and failure of the spleen to transport and transform; diarrhea following abdominal pain before dawn, marked by loose stool with indigested food, is called morning diarrhea, usually resulting from decline of fire in mingmen (vital gate) and internal accumulation of yin cold and damp turbidity; diarrhea following abdominal pain and often worsened by emotional upsets is frequently caused by imbalance between the liver and the spleen.