In the zang-xiang theory, there is a close relationship between emotional changes and the functions of the internal organs. This is primarily expressed through the theory of “the five zang organs corresponding to the emotions”: As stated in Suwen (Plain Questions), chapter Yinyang Yingxiang Dalun (Great Treatise on the Correspondences of Yin and Yang), “The emotion of the heart is joy, the emotion of the liver is anger, the emotion of the spleen is overthinking, the emotion of the lung is grief, and the emotion of the kidney is fear.”

The heart is related to the emotion of “joy”. Moderate joy allows the heart qi to flow smoothly and harmonises qi and blood. However, excessive joy may cause the heart qi to overflow, manifesting as restlessness, insomnia, and palpitations.

The liver is related to the emotion of “anger”. When anger surges upward, it causes the liver qi to ascend counterflow, driving qi and blood to rush to the head. Prolonged irritability damages the liver, resulting in symptoms of liver yang hyperactivity such as headache, reddened eyes, and distending pain in the chest and hypochondria.

The spleen is related to the emotion of “overthinking”. Excessive overthinking injures the spleen qi, leading to manifestations of spleen and stomach dysfunction such as poor appetite and indigestion. Over time, this may impair the generation of qi and blood, resulting in a sallow complexion, physical weakness, and fatigue.

The lung is related to the emotion of “grief”. Excessive grief depletes lung qi, leading to shortness of breath, fatigue, listlessness, and even impaired respiratory function.

The kidney is related to the emotion of “fear”. Excessive fear injures the kidney, causing kidney qi to become unfixed, which manifests as soreness and weakness of the lower back and knees, seminal emission, and urinary or faecal incontinence — symptoms of kidney deficiency.

Emotional imbalance not only directly damages the five zang organs, but can also further exacerbate pathological changes in the body by disrupting the circulation of qi and blood, the metabolism of body fluids, and other physiological processes. The harmonisation of emotions is a vital component in maintaining the normal function of the zang-fu organs. Through proper emotional management, one can effectively prevent and treat zang-fu organ dysfunction caused by emotional imbalance.