The relationships among the six fu-organs mainly involve the coordination in the process of digesting, absorbing and excreting food. After primary digestion in the stomach, food is transmitted to the small intestine where the chyme is further digested by separating the lucid from the turbid. At the same time the gallbladder excretes bile into the small intestine to promote digestion. 

After absorption, the small intestine transports food nutrients upwards to the heart and the lung to nourish the whole body. The rest of water is transformed by the kidney into urine and transmitted to the bladder. Thus the .small intestine transmits the waste of food to the large intestine where part of the water in the waste is absorbed and the rest is transformed into feces to be excreted out of the body. The triple energizer, the passage of water with its qi flowing from the upper to the lower, is also involved in the digestion, absorption and excretion of food. 

Generally speaking, digestion is accomplished by coordinative action of the stomach, the gallbladder and the small intestine; absorption mainly takes place in the small intestine, but the large intestine also absorbs part of water; excretion is accomplished by the bladder and the large intestine.

      

The six fu-organs mainly function to transport and transform food and water. So they constantly receive, transmit and excrete. When food and water are transmitted from the upper to the lower, the stomach and the intestines alternate with the states of fullness and emptiness so as to keep an unobstructed condition. That is why it is said that "the six fu-organs function well when they are not obstructed" and that "the disorder of the fu-organs can be treated by dredging therapy". 

Clinically disorders of the six fu-organs tend to affect each other. For example, failure of the gallbladder to dredge and disperse will affect the stomach, leading to hypochondriac pain, jaundice, poor appetite and vomiting due to dysfunction of both the gallbladder and the stomach. Consumption of fluid by excess-heat in the stomach will obstruct the large intestine, causing constipation.