I. Definition and Characteristics of Ruyi Tongue

1. Naming and Morphology of Ruyi Tongue

• ​Naming Basis: Ruyi tongue refers to a tongue shape that is concave in the upper and lower parts, resembling a ruyi. It is convex in the middle, concave at both ends, with a dry and concave tongue root.

• ​Tongue Image Classification: Type Tongue Image Characteristics Corresponding Pathogenesis Yin Deficiency Ruyi Tongue Concave tongue root, white greasy or peeled coating Deficiency of lower yuan, hyperactive superficial yang Yang Deficiency Ruyi Tongue Concave tongue root, pale and tender tongue without coating Insufficient kidney yang, failure to transform water and dampness

2. Analysis of Tongue Image Atlas

• ​Figure 1: Concave anterior tongue with cracks, white greasy tongue root (Yin deficiency with hyperactive fire)

• ​Figure 2: Concave tongue root with white slippery coating, teeth marks on the tongue edges (Yang deficiency with water retention)

• ​Figure 3: Concave middle tongue with spots (Deficiency of both qi and yin)

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​II. Pathogenesis Analysis: Deficiency of Lower Yuan and Sinking of Zong Qi

1. Pathological Mechanism of Deficiency of Lower Yuan

The pathogenesis of Ruyi tongue is often due to deficiency of lower yuan, with the upper qi sinking.

• ​Insufficient Kidney Essence: Soreness and weakness in the waist and knees, frequent nocturnal urination (Kidney yin deficiency: five-center heat; Kidney yang deficiency: fear of cold and cold limbs).
• ​Correlation with Tongue Image: The degree of concavity at the tongue root is positively correlated with the deficiency of kidney essence (the more concave the tongue root, the more severe the kidney deficiency) and the sides of the tongue root are also relatively narrow.

2. Pathological Mechanism of Sinking of Upper Zong Qi

• ​Function of Zong Qi: Zhang Xichun in “Medical Insights from East and West”: “Zong qi governs respiration and penetrates the heart pulse.”
• ​Symptom Manifestation: Palpitations, shortness of breath, chest tightness, and fatigue (concave anterior tongue with cracks).
• Diagnosis by Tongue: Patients often exhibit weakness and soreness in the waist and legs. Depending on whether it is yang deficiency or yin deficiency, there may be cold feet or hot soles, or both yin and yang deficiency, with both cold and hot feet present. (Here, only high-frequency symptoms based on tongue diagnosis are mentioned.)

3. Treatment Plan by Syndrome Differentiation

Prescription Based on Tongue: Kidney essence tonifying herbs are generally used, as a concave tongue root indicates a deficiency of substantial matter.

If there is kidney yang deficiency, options include Du Zhong, Xu Duan, Gou Ji, and Lu Jiao Jiao. If there is kidney yin deficiency, options include Shu Di Huang, Shan Zhu Yu, and Gui Ban. Specific prescriptions depend on individual habits and whether there is hyperactive fire. If there is yin deficiency with hyperactive fire, Yin Fire Decoction can be used. For yang deficiency with floating superficial yang, Qian Yang Feng Sui Dan can be used. When to use Fu Zi and Rou Gui depends on the situation.

Analysis: The condition of lower yuan deficiency varies, possibly manifesting as a concave tongue root, dryness, redness, even cracks, and no coating, mainly due to yin deficiency. It may also manifest as a white greasy coating, mainly due to yang deficiency.

It should be noted that if the tongue root has no coating and is not red, appearing pale and tender, this is also a sign of yang deficiency. Due to yang deficiency, water cannot be vaporized and rise, hence the pale and tender appearance without coating.

A concave tongue root is often formed over a long period. In men, it may be due to chronic masturbation or excessive sexual activity. In women, it may be seen in cases of prolonged menstrual spotting or heavy menstrual bleeding.

​Syndrome Type	​Core Symptoms	​Recommended Formulas
Kidney Yin Deficiency	Red tongue with little coating, hot soles	Zuogui Wan + Gui Ban Jiao
Kidney Yang Deficiency	Pale and swollen tongue with white coating, cold feet, frequent urination	Yougui Wan + Lu Jiao Jiao
Sinking of Zong Qi	Concave anterior tongue, shortness of breath on exertion	Buzhong Yiqi Tang + Shengma Gegen Tang

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​III. Clinical Cases and Adjustment Guidelines

1. Analysis of Typical Cases

Tongue Image and Pathogenesis: Those with sinking of upper qi (zong qi) often exhibit a concave anterior tongue, which may also have cracks inside the concavity. For example, the following tongue image.

Diagnosis by Tongue: Patients often experience palpitations, shortness of breath, fatigue, and chest tightness. This is because zong qi governs the function of the upper heart and lungs, and its deficiency manifests in heart and lung function issues.

Prescription Based on Tongue: Generally, Li Dongyuan’s Buzhong Yiqi Tang and Zhang Xichun’s Shengxian Tang are considered.

A separate article will be written about the tongue image of upper qi sinking, so it will not be detailed here.

Note: The last two tongue images are supplementary explanations; for Ruyi tongue, please refer to the first three tongue images.

• ​Case 1: Male, 35 years old, concave tongue root with white greasy coating, main complaint of waist soreness and fatigue, diagnosed as kidney yang deficiency, treated with Yougui Wan for 2 months, after which the tongue coating turned thin and white.
• ​Case 2: Female, 42 years old, concave anterior tongue with cracks, accompanied by palpitations and insomnia, diagnosed as sinking of zong qi, treated with Shengxian Tang plus 10g of Dan Shen, after which chest tightness was relieved in 1 month.

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​IV. Key Points of TCM Syndrome Differentiation and Contraindications

1. Core of Ruyi Tongue Syndrome Differentiation

• ​Essential Symptoms to Ask: Condition of the waist and knees, frequency of nocturnal urination, temperature of hands and feet.
• ​Essential Signs to Check: Depth of tongue root concavity, moisture of tongue coating.

2. List of Contraindicated Medications

​Syndrome Type	​Contraindicated Medications	​Risk Warning
Kidney Yin Deficiency with Hyperactive Fire	Fu Zi, Rou Gui	Assists fire and injures yin, exacerbating hot flashes and night sweats
Sinking of Zong Qi with Dampness Obstruction	Yin-nourishing herbs (such as Shu Di Huang)	Sticky and greasy, hinders the spleen, exacerbates qi stagnation and chest tightness

Note: The treatment methods and medications mentioned in the text are for reference by TCM practitioners only. Patients should not self-medicate, as they do so at their own risk.