Dashu (Great Heat): TCM Guide to Clearing Summer Heat and Damp

Direct Answer: What Is Dashu in TCM?

Dashu (大暑), meaning "great heat," is the twelfth solar term, usually falling around July 22 to 24. It marks the absolute peak of summer heat and the most humid period of the year. In TCM, this is when two pathogens — the Heat evil (re xie) and the Dampness evil (shi xie) — combine to form damp-heat (shi re), the most stubborn and complex pathogen combination in Chinese medicine. Heat is a Yang pathogen that rises upward and consumes fluids; Dampness is a Yin pathogen that is heavy, sinking, and sticky. Together, they create a pattern that is simultaneously drying and heavy, acute and chronic — and notoriously difficult to treat because cooling the heat can worsen the dampness, while drying the dampness can intensify the heat. To navigate Dashu, the body needs Heart and Spleen dual care: the Heart (Fire element) must be protected from the Heat evil, while the Spleen (Earth element) must be supported against the Dampness evil. Eat winter melon to clear heat and promote urination, bitter melon to clear heat and resolve dampness, and drink lotus leaf tea to clear summer heat while raising clear Yang against the heavy, sinking nature of dampness. Cooling porridge (congee) made with mung beans, winter melon, or lotus seeds is the ideal Dashu staple — it clears heat gently while nourishing the Spleen. Above all, avoid overexertion: profuse sweating depletes Heart Qi and body fluids, and the Huangdi Neijing explicitly warns against exhausting the body in peak summer. See our cooling foods guide and summer wellness guide for detailed seasonal practices.

The TCM Framework: Damp-Heat and Dual Organ Care

Aspect	Dashu Correspondence
Primary pathogen	Damp-Heat (shi re) — the most stubborn combination
Organs requiring care	Heart (Heat) and Spleen (Dampness) — dual care required
Elements	Fire (Heart) and Earth (Spleen)
Climate	Hottest and most humid period of the year
Heat characteristics	Rises upward, consumes Qi and fluids, disturbs Shen
Dampness characteristics	Heavy, sinking, sticky, obstructs qi flow, burdens the Spleen
Damp-heat symptoms	Heavy body, sticky sweat, poor appetite, bloating, dark urine, thick yellow tongue coating
Severe manifestation	Exhaustion of Qi and fluids, heatstroke, damp-heat skin eruptions

The Huangdi Neijing describes the relationship between Heat and Dampness in summer. Heat is a Yang pathogen that "scorches and consumes," while Dampness is a Yin pathogen that is "heavy, turbid, and粘滞 (sticky and stagnant)." Their combination creates unique challenges:

• Opposing natures: Heat rises upward; Dampness sinks downward. The body is pulled in two directions simultaneously, creating a feeling of being overheated yet weighed down.
• Sticky and stubborn: Damp-heat is the most difficult pattern to resolve. It lingers, recurs, and resists simple treatment because addressing one aspect can aggravate the other.
• Burdens two organ systems: The Heat evil taxes the Heart (the Fire organ), while the Dampness evil burdens the Spleen (the Earth organ). Both must be cared for, and what helps one can harm the other if not balanced carefully.
• Obstructs the middle burner: Damp-heat commonly settles in the Spleen and Stomach (the middle burner), causing poor appetite, nausea, bloating, and a feeling of fullness and heaviness.

The Heart in Peak Heat

The Heart belongs to the Fire element and is the organ most directly affected by summer Heat. During Dashu, the Heart works hardest:

• Heat disturbs the Shen: The Heart houses the Shen (mind and spirit). When Heat invades, the mind becomes restless, causing insomnia, agitation, vivid dreams, and in severe cases, confusion or delirium.
• Sweating depletes Heart Qi: In TCM, sweat is the fluid of the Heart. Profuse sweating during peak heat directly depletes Heart Qi and Yin, leading to fatigue, palpitations, shortness of breath, and a feeling of emptiness in the chest.
• Heat consumes Heart fluids: The Heart needs adequate Yin (cooling fluid) to balance its Yang (warming, active energy). Summer heat consumes Heart Yin, creating Heart fire symptoms: mouth ulcers, red face, agitation, and a rapid pulse.
• Peak time vulnerability: The Heart's peak time is 11 AM to 1 PM (midday), which is also when the heat is most intense. This is why midday rest is critical during Dashu.

The Spleen Under Dampness

The Spleen belongs to the Earth element and is the organ most vulnerable to Dampness. During Dashu, the Spleen is under siege:

• Dampness burdens the Spleen: The Spleen's function is to transform and transport fluids and nutrients. When external dampness (humidity) combines with internal dampness (from poor diet), the Spleen becomes sluggish, causing poor appetite, bloating, loose stools, and fatigue.
• Dampness is heavy and sinking: Unlike Heat which rises, Dampness sinks and creates a heavy feeling in the body — heavy limbs, clouded thinking, a feeling of being weighed down.
• The Spleen dislikes cold and damp: The Spleen needs warmth and dryness to function. Excess cold foods (ice water, ice cream) and damp-generating foods (greasy, sweet, dairy) further impair the Spleen during Dashu.
• Damp-heat in the middle burner: When damp-heat settles in the Spleen and Stomach, it creates a distinct pattern: a heavy, full feeling in the chest and abdomen, nausea, sticky mouth, thirst without desire to drink, and a thick, yellow, greasy tongue coating.

Actionable Steps: Dashu Wellness Practices

1. Eat Damp-Heat-Clearing Foods

Dashu demands foods that address both Heat and Dampness simultaneously:

• Winter melon (冬瓜, dong gua): The quintessential Dashu food. Clears heat, promotes urination, and resolves dampness. It is cool but not cold, making it safe for the Spleen. Winter melon soup is the classic Dashu dish. See our cooling foods guide.
• Bitter melon (苦瓜, ku gua): Clears heat, resolves dampness, cools blood, and detoxifies. The bitter flavor in TCM descends and dries — ideal for damp-heat that tends to rise upward and create stickiness. Stir-fry with eggs or blanch and dress with sesame oil and vinegar.
• Lotus root (莲节): Cools blood, clears Heart heat, and stops bleeding. Lotus seed (lian zi) calms the Shen and strengthens the Spleen — addressing both organs of Dashu.
• Mung beans (绿豆): Clear heat, detoxify, and drain dampness. Mung bean soup remains the essential summer beverage, but during Dashu, it should be combined with warming or Spleen-supporting ingredients like dried tangerine peel (chen pi) or a slice of fresh ginger to protect the Spleen.
• Coix seed / Job's tears (茅仁, yi yi ren): The most important damp-draining grain in TCM. It strengthens the Spleen, drains dampness, and clears mild heat. Cook in congee with mung beans for the perfect damp-heat-clearing meal.
• Watermelon: Still excellent for clearing summer heat and generating fluids, but eat in moderation during Dashu — its cold nature can burden the Spleen if consumed excessively in humid weather.

2. Drink Lotus Leaf Tea and Cooling Teas

Teas during Dashu should clear heat while addressing dampness:

• Lotus leaf tea (荷叶茶): The signature Dashu tea. Clears summer heat, raises clear Yang, and resolves dampness. Its light, upward nature directly counters the heavy, sinking quality of damp-heat. Steep fresh or dried lotus leaves in hot water with a little rock sugar.
• Chrysanthemum tea: Clears heat from the Liver and eyes, calms the mind, and gently cools without being too cold. See our chrysanthemum tea guide.
• Sour plum drink (suan mei tang): Made from smoked plums, hawthorn, licorice, and rock sugar. Generates fluids, quenches thirst, and gently cools — ideal for the fluid-depleting heat of Dashu.
• Mung bean water: The cooking liquid from boiled mung beans, drunk cool (not cold), gently clears heat and detoxifies. Add dried tangerine peel (chen pi) to support the Spleen.
• Honeysuckle tea (jin yin hua): Clears heat and detoxifies. Especially useful if damp-heat causes skin eruptions or sore throat. Combine with chrysanthemum for a more comprehensive heat-clearing effect.

3. Eat Cooling Porridge (Congee)

Congee (zhou) is the single most important food during Dashu. It is the TCM solution to the damp-heat dilemma — cooked and warm (protecting the Spleen) yet made with heat-clearing ingredients (protecting the Heart):

• Mung bean and coix seed congee: The classic Dashu congee. Mung beans clear heat and detoxify; coix seed strengthens the Spleen and drains dampness. Together, they address both aspects of damp-heat. Cook 1 part mung beans, 1 part coix seed, and 2 parts rice in plenty of water until soft and porridge-like.
• Winter melon congee: Dice winter melon and cook with rice into a light congee. Clears heat, promotes urination, and resolves dampness. Add a few dried shrimp or a little ginger for flavor and Spleen support.
• Lotus seed and lily bulb congee: Lotus seeds calm the Shen and strengthen the Spleen; lily bulbs (bai he) clear Heart heat and calm the mind. This congee is ideal for the insomnia and agitation that damp-heat causes.
• Yam (shan yao) congee: Chinese yam strengthens the Spleen, nourishes the Stomach, and gently tonifies Qi. For those whose Spleen has been damaged by summer cold foods, this congee helps restore digestive function.

For the full seasonal eating framework, see our summer wellness guide.

4. Avoid Overexertion — The Key Dashu Principle

The Huangdi Neijing is explicit: in summer, one should not overexert. During Dashu, this becomes the single most important lifestyle principle:

• Sweating depletes Heart Qi: In TCM, "sweat is the fluid of the Heart." Profuse sweating from intense exercise does not just lose water — it directly depletes Heart Qi and Heart Yin, leading to fatigue, palpitations, shortness of breath, and lowered immunity.
• The Heart is already stressed: During Dashu, the Heart is working hardest to circulate blood to the skin surface for cooling. Adding the burden of strenuous exercise overloads the system.
• Heat exhaustion vs. gentle movement: Instead of running, hiking, or heavy workouts, choose walking, tai chi, qigong, or gentle stretching in the early morning (before 8 AM) or evening (after 6 PM). The goal is to move qi without exhausting it.
• The Neijing principle: Suwen Chapter 2 advises that in summer, one should "sweat, letting the sweat flow out" — but this refers to gentle, natural perspiration from mild activity and warmth, not the drenching sweat of intense exercise. The distinction is critical: light sweating opens the pores and releases heat; profuse sweating depletes the body.

5. Press Heart-Soothing and Spleen-Strengthening Points

Two sets of points are essential during Dashu — one for the Heart, one for the Spleen:

• Neiguan (PC6): On the inner forearm, 3 finger-widths above the wrist. Calms the Heart, clears heat, relieves nausea (common with damp-heat in the middle burner), and soothes the Shen. Press for 1 to 2 minutes per arm.
• Shenmen (HT7): On the wrist crease, toward the little finger side. Calms the Heart, clears Heart fire, and treats insomnia and agitation. Press for 1 minute per wrist, especially before sleep.
• Zusanli (ST36): Below the knee, on the outer side of the shin. The most important Spleen-strengthening point in TCM. Strengthens the Spleen, resolves dampness, and supports the body during the depleting heat. Press firmly for 2 to 3 minutes per leg.
• Yongquan (KD1): On the sole of the foot. Draws heat downward from the head and Heart, grounding the rising Yang of summer heat. Press for 1 to 2 minutes per foot before sleep to calm the mind and clear Heart fire.

Contraindications and Precautions

• Heatstroke is an emergency: If you or someone else shows signs of heatstroke — confusion, loss of consciousness, hot dry skin with no sweat, extremely high body temperature — call emergency services immediately. Do not attempt to treat heatstroke with food or tea alone.
• Cardiovascular conditions: Peak heat stresses the heart more than any other season. If you have heart disease, hypertension, or take cardiac medications, stay indoors during peak heat hours, monitor blood pressure, and follow your cardiologist's recommendations.
• Damp-heat skin conditions: If you have eczema, acne, or fungal skin conditions that worsen in humidity, these may be damp-heat patterns. Avoid greasy, sweet, and spicy foods. Consult a TCM practitioner for a personalized herbal formula.
• Cold-deficient constitution: If you tend toward cold and Spleen deficiency, use cooling foods cautiously. Balance winter melon and bitter melon with warming ginger, dried tangerine peel (chen pi), and cooked foods.
• Dehydration and electrolyte balance: If you take diuretics or have kidney issues, monitor fluid and electrolyte intake carefully. Profuse sweating in peak heat can cause dangerous electrolyte imbalances — consult your doctor.
• Excessive bitter foods: While bitter melon is excellent for damp-heat, too much bitter flavor can injure the Spleen and Stomach. Balance bitter foods with sweet-natured grains and root vegetables.

References and Classical Sources

• Huangdi Neijing (Yellow Emperor's Inner Canon), circa 200 BCE — Suwen Chapter 2: Summer living principles and the warning against overexertion. Suwen Chapter 5: Fire and Earth element correspondences. Suwen Chapter 31: Heat evil pathology. Suwen Chapter 74: Damp-heat treatment principles and the strategy of clearing heat without worsening dampness.
• Bencao Gangmu by Li Shizhen, 1578 — Documents winter melon as clearing heat and promoting urination, bitter melon as clearing heat and resolving dampness, lotus leaf as clearing summer heat and raising clear Yang, and coix seed as strengthening the Spleen and draining dampness.
• Shanghan Lun by Zhang Zhongjing, circa 220 CE — Contains formulas for damp-heat patterns, including formulas that use coix seed (Yi Yi Ren) as a key ingredient for draining dampness while clearing heat.
• Wenbing Xue (Warm Disease School) — The later TCM tradition (Ming-Qing dynasty) that developed the most sophisticated understanding of summer-heat and damp-heat patterns, including the principle that damp-heat must be treated by simultaneously cooling and draining, using light, aromatic, and diuretic substances.

Related Tools and Resources

• Cooling Foods for Heat Relief — Complete guide to heat-clearing foods including winter melon and bitter melon.
• Chrysanthemum Tea Guide — Using chrysanthemum to clear heat and calm the mind during peak summer.
• Summer Wellness Guide — Full summer seasonal wellness framework with foods, teas, and practices.
• TCM Constitution Quiz — Check your pattern and get personalized Dashu recommendations.

The Bottom Line

Dashu is the crucible of summer — the hottest and most humid period of the year, when the Heat evil and Dampness evil combine into the most stubborn pathogen in all of Chinese medicine: damp-heat. This combination demands a dual strategy: care for the Heart (stressed by Heat) and the Spleen (burdened by Dampness) simultaneously. The TCM answer to this challenge is elegant in its simplicity: winter melon clears heat and drains dampness through urination; bitter melon clears heat and dries dampness through its descending, bitter nature; lotus leaf tea clears summer heat while raising the clear Yang against the heavy, sinking force of dampness; and cooling porridge — cooked, warm, and easy to digest — clears heat from within while protecting the Spleen that cold foods would damage. The single most important lifestyle principle is avoiding overexertion. The Huangdi Neijing is clear: in peak summer, the body must not be exhausted. Profuse sweating does not detoxify — it depletes Heart Qi and body fluids. Gentle movement in the cool hours replaces strenuous exercise. Press Neiguan (PC6) to calm the Heart, Zusanli (ST36) to strengthen the Spleen, and Yongquan (KD1) to draw heat downward before sleep. Dashu is the test of summer wisdom: those who cool gently, eat porridge, rest at midday, and move softly will pass through the year's most punishing days with their Qi intact and their organs balanced. This is not the time to fight the heat — it is the time to flow with it, nourished by the very foods that nature provides in this exact season.