Bai Hu Tang: A TCM Formula for Clearing Heat and Restoring Fluids in Yangming Syndrome
Hongji Medical- 10 hours ago
- 4 min read
Bai Hu Tang, from Zhang Zhongjing’s Treatise on Cold Damage Diseases (Shang Han Lun) of the Eastern Han Dynasty, is a classic Chinese medicine formula.
Zhang Zhongjing, known as the “Sage of Medicine,” laid the foundation for Chinese medicine’s syndrome differentiation and treatment.
Bai Hu Tang is mainly used to treat Yangming syndrome, a condition in the Six-Channel Differentiation, and is renowned for its strong heat-clearing and fluid-generating effects, widely applied by later generations of practitioners.
Bai Hu Tang Formula Explanation
Bai Hu Tang consists of four herbs, combined according to the "monarch, minister, assistant, and envoy" principle:
Monarch Herb: Shi Gao (Gypsum)Shi Gao, with its pungent, sweet, and cold properties, clears heat from the lungs and stomach and promotes sweating.
Modern physician Zhang Xichun noted that while Shi Gao’s cooling effect is milder than herbs like Huang Lian, Long Dan Cao, Zhi Mu, or Huang Bai, its ability to reduce fever surpasses them. It expels internal heat through the pores, effectively cooling the body.
Minister Herb: Zhi Mu (Anemarrhena)Zhi Mu, bitter and cold but non-drying, nourishes yin fluids and promotes fluid generation. Paired with Shi Gao, it clears heat, provides a pathway for heat to exit, and protects stomach fluids from prolonged heat damage.
Assistant Herb: Gan Cao (Licorice)Gan Cao, sweet and mild, moderates Shi Gao’s cold nature to prevent excessive cooling. It also harmonizes the formula, boosts qi, and balances the stomach.
Envoy Herb: Jing Mi (Non-Glutinous Rice)Jing Mi (rice) generates fluids, protects the stomach, and balances Shi Gao’s cold nature, making it gentler on the stomach.
Together with Gan Cao, it nourishes stomach qi and fluids, preventing adverse effects from Shi Gao’s coldness while allowing Shi Gao and Zhi Mu to clear lung and stomach heat effectively and protect vital fluids and qi.
Pathophysiology of Bai Hu Tang
Bai Hu Tang targets Yangming syndrome, characterized by intense internal heat. This condition causes persistent high fever, forcing body fluids outward as excessive sweat and leading to constipation due to impaired intestinal function.
Patients often experience extreme thirst, craving cold water to relieve heat. The internal heat travels along the stomach meridian to the head and face, causing facial redness, heat intolerance, and no fear of cold. Other symptoms include body heaviness, headaches, irritability, and a strong, flooding, or slippery pulse.
Bai Hu Tang’s combination clears lung and stomach heat, generates fluids, quenches thirst, and restores internal heat balance.
Shi Gao and Zhi Mu clear heat, relieve irritability, and promote fluid production, while Gan Cao and Jing Mi harmonize the formula, protect stomach qi, and prevent damage from cold herbs.
Effects of Bai Hu Tang
Bai Hu Tang’s main effects are clearing heat and generating fluids, making it ideal for Yangming syndrome symptoms like high fever, thirst, and excessive sweating. Its indications include:
High Fever: Persistent fever with facial redness, thirst for cold water, sweating, and heat intolerance.
Thirst: Intense thirst with a preference for cold drinks to cool the body.
Excessive Sweating: Profuse sweating due to heat forcing fluids out.
Pulse: Strong, flooding pulse reflecting intense internal heat.
Modern Applications of Bai Hu Tang
Modern pharmacology shows Shi Gao reduces fever, possibly by calming the body’s temperature regulation center, enhancing plasma protein binding, increasing free water for heat dissipation, and inhibiting acetylcholine release to reduce sweating.
Zhi Mu contains sterols, flavonoids, volatile oils, and organic acids, offering anti-inflammatory, antibacterial, antiviral, antioxidant, heat-clearing, fluid-generating, and diuretic effects.
Gan Cao contains glycyrrhizic acid, glycyrrhizin, and rutin, providing detoxification, anti-inflammatory, anti-allergic, cough-relieving, phlegm-clearing, and antiviral effects. Jing Mi (rice) provides proteins, fats, carbohydrates, vitamins, and minerals, supporting nutrition, energy, physiological balance, and bone health.
Bai Hu Tang is widely used in modern medicine for conditions with high fever, thirst, and sweating, such as viral colds, lobar pneumonia, and epidemic encephalitis B.
These conditions often involve persistent fever, thirst, and sweating, which Bai Hu Tang effectively relieves through its heat-clearing and fluid-generating effects.
In metabolic disorders like diabetes, which present with high blood sugar, excessive thirst, and frequent urination—similar to Yangming syndrome—Bai Hu Tang regulates heat balance, reduces thirst, and improves metabolism.
It is also valuable for stroke, acute gouty arthritis, heatstroke, and peripheral neuralgia, where its heat-clearing and anti-inflammatory effects reduce inflammation and protect tissues.
Modern studies confirm Bai Hu Tang’s fever-reducing, anti-inflammatory, and immune-boosting effects, providing a scientific basis for its clinical value. However, attention to contraindications and indications is essential for safe and effective use.
Precautions
When using Bai Hu Tang, note the following:
Contraindications: Avoid in cases of floating pulse, fever without sweating, or unresolved exterior symptoms. It is also unsuitable for patients with a thin, wiry, or sunken pulse, no thirst, or no sweating.
Yang Deficiency Fever: Avoid in cases of spleen-stomach weakness, yang qi overflow, self-sweating, fatigue, aversion to wind, or weak pulse to prevent harming yang qi.
True Cold with False Heat: Avoid in cases of yin excess with yang rejection.
Conclusion
Bai Hu Tang, a classic Chinese medicine formula, is highly effective for clearing heat and generating fluids, widely used for various conditions. Its precise combination of herbs, balanced by the monarch-minister-assistant-envoy principle, clears internal heat and protects fluids and qi.
Modern research confirms its fever-reducing and immune-enhancing effects, enhancing its clinical value. Careful attention to indications and contraindications ensures safe and effective use.
