San Ren Tang: A Traditional Chinese Herbal Remedy for Clearing Dampness and Heat
Hongji Medical- Feb 2
- 7 min read
San Ren Tang, also known as Three Kernels Decoction, is a classic Chinese herbal formula from the Wen Bing Tiao Bian (Treatise on Warm Diseases). Renowned for promoting qi flow and clearing dampness and heat, it’s especially effective for the early stages of damp-heat syndromes, particularly in hot, humid summer weather.
This gentle remedy relieves symptoms like fatigue, bloating, and headaches caused by dampness overpowering heat. This article explores its ingredients, benefits, modern uses, dietary support, and precautions in a clear, approachable way, using common plant names.
Ingredients of San Ren Tang
San Ren Tang combines eight herbs, each contributing to its therapeutic effects:
Xing Ren (Almond, 15g): Clears lung heat and promotes qi flow.
Hua Shi (Talc, 18g): Clears heat and promotes urination.
Tong Cao (Rice Paper Pith, 6g): Enhances urination and clears dampness.
Bai Dou Kou (White Cardamom, 6g): Dries dampness and supports digestion.
Dan Zhu Ye (Bamboo Leaf, 6g): Clears heat and relieves irritability.
Hou Po (Magnolia Bark, 6g): Dries dampness and promotes qi movement.
Sheng Yi Mi (Coix Seed, 18g): Clears dampness and supports the spleen.
Ban Xia (Pinellia, 15g): Dries dampness and relieves nausea.
Preparation: Boil the herbs in water, strain, and take the decoction three times daily. Modern methods may use pre-made pills or powders, dosed as prescribed by a practitioner.
How the Herbs Work Together
San Ren Tang follows the traditional Chinese medicine principles of monarch, minister, assistant, and envoy:
Xing Ren (Almond): The primary herb (monarch), it promotes lung qi flow, clears heat, and helps expel dampness from the upper body.
Hua Shi (Talc) and Sheng Yi Mi (Coix Seed): Minister herbs, they clear heat, promote urination, and address dampness in the middle and lower body.
Bai Dou Kou (White Cardamom) and Hou Po (Magnolia Bark): Assistant herbs, they dry dampness, support spleen and stomach function, and relieve bloating.
Tong Cao (Rice Paper Pith) and Dan Zhu Ye (Bamboo Leaf): Assistant herbs, they guide the formula’s effects to the lower body, enhancing urination and clearing heat.
Ban Xia (Pinellia): An envoy, it dries dampness, resolves phlegm, and stops vomiting, supporting digestive comfort.
This balanced blend clears damp-heat, promotes qi flow, and restores harmony across the body’s three burners (upper, middle, and lower regions).
San Ren Tang
Effects and Indications
Main Effects:
Promotes qi flow to relieve stagnation.
Clears dampness and heat to restore balance.
Supports spleen and stomach function for better digestion.
Indications: San Ren Tang is used for early-stage damp-heat syndromes where dampness outweighs heat, with symptoms including:
Headache and sensitivity to cold
Heaviness and pain in the body
Fatigue and limb weakness
Chest tightness and poor appetite
Afternoon fever (typically between 3-7 PM)
Pale complexion
White tongue coating without thirst
Stringy, moist pulse
These symptoms often arise in humid, warm weather or from dietary imbalances, where dampness blocks qi flow and impairs digestion.
Benefits of San Ren Tang
Clears Damp-Heat: Relieves headaches, fever, and fatigue caused by dampness and heat.
Eases Digestive Discomfort: Reduces bloating, chest tightness, and poor appetite.
Boosts Energy: Alleviates heaviness and tiredness in the body.
Supports Urinary Health: Promotes urination to clear excess dampness.
Pathogenesis
Damp-heat syndromes occur when external humidity and heat combine with internal dampness, often from poor diet or weak spleen function. This dampness blocks the body’s wei yang (defensive energy), causing chills and headaches, and burdens the spleen and stomach, leading to chest tightness and loss of appetite.
Afternoon fever arises as dampness, a yin pathogen, peaks between 3-7 PM. San Ren Tang clears damp-heat and restores qi flow to alleviate these symptoms.
Modern Applications
San Ren Tang is widely used in modern medicine for:
Digestive disorders: Treats gastroenteritis, bloating, and diarrhea caused by damp-heat in the spleen and stomach.
Skin conditions: Manages eczema and itching due to damp-heat in the skin.
Summer colds: Relieves headaches, fatigue, and heaviness in humid, warm weather.
Urinary issues: Supports treatment of urinary tract infections with damp-heat symptoms.
Its anti-inflammatory and diuretic properties make it effective for damp-heat-related conditions across multiple systems.
Dietary Support
Pairing San Ren Tang with dietary remedies can enhance its effects, especially in humid summer months:
San Ren Porridge: Cook 30g coix seed, 50g rice, 6g white cardamom, and 5g fried sweet almonds (skin and tip removed) into porridge. Add cardamom and almonds 5 minutes before serving. Eat 1-2 times daily for 3-5 days to clear dampness and support digestion.
Coix Seed Soup: Boil 30g coix seed with 100g lean pork. This clears dampness and strengthens the spleen.
Bamboo Leaf Tea: Steep 10g bamboo leaf in boiling water for 10 minutes. Drink twice daily to clear heat and relieve irritability.
These recipes complement the formula’s dampness-clearing and qi-promoting effects, aiding recovery. Avoid mung bean soup in humid weather, as it may over-dampen the spleen.
Precautions
Use San Ren Tang cautiously:
Contraindications: Avoid in cases where heat outweighs dampness or in yin deficiency with hot flashes. Misdiagnosis may worsen symptoms.
Three taboos (from Treatise on Febrile Diseases):
Do not induce sweating for headaches and chills, as it may harm heart yang, causing dizziness or deafness.
Do not use laxatives for chest tightness and poor appetite, as they may damage the spleen and worsen diarrhea.
Do not use yin-nourishing drugs for afternoon fever, as they trap dampness.
Dietary restrictions: Avoid greasy, spicy, or raw foods during treatment.
Professional guidance: Consult a Chinese medicine practitioner to ensure proper syndrome differentiation and avoid drug interactions.
Storage: Keep in a cool, dry place, away from sunlight. Do not use expired medicine.
If discomfort occurs, stop use and consult a doctor.
Conclusion
San Ren Tang is a powerful Chinese herbal formula that clears dampness and heat, promotes qi flow, and relieves symptoms like fatigue, bloating, and headaches. Its carefully balanced herbs make it ideal for early-stage damp-heat syndromes, particularly in humid summer weather.
Modern applications for gastroenteritis, eczema, and summer colds highlight its versatility. With proper use, dietary support like San Ren Porridge, and professional guidance, San Ren Tang can restore balance and improve overall well-being.
Chinese Name | 三仁湯 |
Phonetic | San Ren Tang |
English Name | Three Kernels Decoction |
Classification | Dampclearing formulas |
Source | 《Systematic Differentiation of Warm Diseases》Wen Bing Tiao Bian《溫病條辨》 |
Combination | Armeniacae Semen Amarum (Xing Ren) 5 qian (15g), Talcum (Hua Shi) 6 qian (18g), Tetrapanacis Medulla (Tong Cao) 2 qian (6g), Amomi Fructus Rotundus (Bai Dou Kou) 2 qian (6g), Lophatheri Herba (Zhu Ye) 2 qian (6g), Magnoliae Officinalis Cortex (Hou Po) 2 qian (6g), Coicis Semen (Yi Yi Ren) 6 qian (18g), Pinelliae Rhizoma (Ban Xia) 5 qian (15g) |
Method | Prepare as a decoction. |
Action | Disperses and diffuses qi movement, clears and removes damp-heat. |
Indication | San Ren Tang is indicated for the pattern of more dampness than heat in the early stage of damp-warmth and summerheat-warmth with dampness. The symptoms are headache, aversion to cold, heavy body, general pain, fatigue, a light yellow complexion, chest distress without hunger, afternoon fever, and no thirst. The tongue coating is white and the pulse is wiry, thin, and soggy. |
Pathogenesis | San Ren Tang is a common formula used in the early stages of damp-warmth where the pathogen is in the qi level with more dampness than heat. Generally, there are two causes for this condition. One is external damp-heat contraction. The other is internal dampness and fluid accumulation with external pathogen contraction. When the internal and external pathogens mix together, damp-warmth is the result. When wei yang is obstructed by dampness, there is headache and aversion to cold. Symptoms such as a heavy body, general pain, and fatigue are induced because of the heavy, turbid nature of dampness. When damp-warmth stagnates in the spleen and stomach, there will be a dysfunction of transformation and a blockage of qi movement causing chest distress without hunger. Dampness is a yin pathogen that is active between 3 to 7 pm. Thereby, afternoon fever results from the conflict between zheng qi and pathogenic qi. |
Clarification | This is a confusing pattern that is easily mistreated. Aversion to cold is caused by dampness blocking wei yang which differs from an exterior pattern. Afternoon fever is caused by damp-heat accumulation which differs from the tidal fever due to yin deficiency. Doctor Wu Tang reported three prohibitions in his Systematic Differentiation of Warm Diseases. First, one is prohibited to induce sweating when aversion to cold and headache are seen because sweating damages heart yang. Unconsciousness, deafness, and an inability to open the eyes and mouth may result otherwise. Second, one is prohibited to apply the purgative method when there is fullness of the middle jiao without hunger because purgatives damage the spleen and stomach. Dampness might invade the lower jiao and lead to through-flux diarrhea as a result. Third, one is prohibited to apply yin-nourishing medicinals when an afternoon fever is seen because dampness is a yin pathogen. Otherwise, the dampness and the yin medicinals might mix to cause a lingering and stubborn pathogen. The correct therapeutic methods are to diffuse and disperse qi movement, clear heat, and drain dampness. |
Application | 1. Essential pattern differentiation San Ren Tang is applicable to patterns of more dampness than heat in the early stages of damp-warmth. This clinical pattern is marked by headache and aversion to cold, heavy body and general pain, fever at afternoon, white tongue coating without thirst. 2. Modern applications This formula may be used in the following biomedically defined disorders when the patient shows signs of dampness more than heat: typhoid, gastroenteritis, pyelonephritis, Brucellosis, glomerulonephritis, and arthritis. 3. Cautions and contraindications This formula is not applicable for patients with heat more than dampness marked by a yellow and greasy tongue coating. |
Additonal formulae | 1. Huo Po Xia Ling Tang (Agastache, Magnolia, Pinellia and Poria Decoction 藿朴夏苓湯) [Source]《Bases of Medicine recorded in A Summary of Externally-contracted Syndromes》Gan Zheng Ji Yao‧Yi Yuan《感證輯要‧醫原》 [Ingredients] Huo xiang 2 qian (6g), ban xia 1.5 qian (4.5g), chi fu ling 3 qian (9g), xing ren 3 qian (9g), yi yi ren 4 qian (12g), bai dou kou 1 qian (3g), tong cao 1 qian (3g), zhu ling 3 qian (9g), dan dou chi 3 qian (9g), ze xie 1.5 qian (4.5g), hou po 1 qian (3g) [Preparation and Administration] Prepare it as a decoction. [Actions] Releases the exterior and removes dampness. [Applicable Patterns] Early stages of damp-warmth. Symptoms include: fever and aversion to cold, fatigue, chest oppression, greasy sensation in the mouth, a thin and white coating, and a soggy and slow pulse. 2. Huang Qin Hua Shi Tang (Scutellaria and Talcum Decoction 黃芩滑石湯) [Source]《Systematic Differentiation of Warm Diseases》Wen Bing Tiao Bian《溫病條辨》 [Ingredients] Huang qin 3 qian (9g), hua shi 3 qian (9g), fu ling pi 3 qian (9g), da fu pi 2 qian (6g), bai dou kou 1 qian (3g), tong cao 1 qian (3g), zhu ling 3 qian (9g) [Preparation and Administration] Prepare it as a decoction. [Actions] Clears heat and drains dampness. [Applicable Patterns] Damp-warmth in the middle jiao. Symptoms include: fever and general pain, the fever feeling as though it has been released with sweating but then recurs, thirst without drink, a light, yellow and wet tongue coating, and a slow pulse. |
