Guyu (Grain Rain): TCM Guide to Damp-Heat Prevention

Direct Answer: What Is Guyu in TCM?

Guyu (稽雨), meaning "grain rain," is the sixth solar term, usually falling around April 19 to 21. It is the last solar term of spring and signifies the rain that nourishes the growing grain. In TCM, Guyu represents a critical shift: temperatures are now consistently warm, and rainfall is at its spring peak. The combination of warming temperatures and high humidity creates the specific pathological pattern of damp-heat (shi re). Damp-heat is a particularly stubborn condition because the heaviness of dampness combines with the intensity of heat, creating a sticky, lingering pattern that is difficult to resolve. It most commonly affects the Spleen (which is weakened by both dampness and heat), the skin (where damp-heat vents as rashes, acne, and eczema), and the urinary system (where it causes dark, scanty, or burning urine). To prevent damp-heat during Guyu, eat foods that simultaneously clear heat and drain dampness — mung beans, coix seed (Job's tears), and winter melon are the key foods. Strengthen the Spleen with cooked, warm, easily digestible foods. Care for the skin by avoiding greasy foods and ensuring proper sweating through gentle exercise. See our dampness-removing foods guide and mung bean congee guide for detailed recipes.

The TCM Framework: Damp-Heat Pattern

Aspect	Guyu Correspondence
Primary pattern	Damp-heat (shi re)
Organs affected	Spleen, Skin, Bladder, Liver
Climate	Warm and humid, frequent rain
Key symptoms	Heaviness, fatigue, skin eruptions, dark urine, sticky mouth, bloating
Treatment principle	Clear heat, drain dampness, strengthen Spleen
Key foods	Mung bean, coix seed, winter melon, green tea

Damp-heat is a compound pathogen in TCM — it combines two of the six external pathogens (dampness and heat) into a single, more complex pattern. The Huangdi Neijing states that in late spring, "dampness and heat contend." The dampness provides a medium for heat to accumulate, and the heat makes the dampness more sticky and resistant. This is why damp-heat conditions tend to be chronic and recurrent — clearing heat alone is not enough if dampness remains, and draining dampness alone is not enough if heat persists. Both must be addressed simultaneously.

How Damp-Heat Manifests in the Body

• Skin: Acne, rashes, eczema flare-ups, oily skin, fungal infections. The skin is the body's largest organ of elimination, and when damp-heat cannot exit through normal channels (urine, stool), it vents through the skin.
• Digestive system: Bloating, nausea, sticky or loose stools with burning sensation, lack of appetite, heavy feeling after eating.
• Urinary system: Dark, scanty, or burning urine, urinary frequency or urgency.
• General: Heaviness in the limbs, fatigue that is worse in the afternoon, foggy thinking with irritability, sticky or bitter taste in the mouth, a thick, yellow, greasy tongue coating.

Actionable Steps: Guyu Wellness Practices

1. Eat Cooling, Dampness-Draining Foods

The dietary principle at Guyu is to simultaneously clear heat and drain dampness:

• Mung beans (绿豆): The most important food for Guyu. They clear heat, detoxify, and drain dampness. Mung bean congee is the classic Guyu dish. See our mung bean congee guide for preparation.
• Coix seed / Job's tears (若籠): Drains dampness, strengthens the Spleen, and clears mild heat. Cook into congee with mung beans for a combined damp-heat-clearing meal.
• Winter melon (冬瓜): Clears heat, promotes urination, and drains dampness. Make winter melon soup with a touch of ginger.
• Cucumber: Cools heat, hydrates, and promotes urination. Eat raw or lightly pickled.
• Green tea: Clears heat, supports detoxification, and contains antioxidants. Drink 1 to 2 cups daily, but avoid on an empty stomach.
• Celery: Clears Liver heat, supports blood pressure, and drains dampness.

2. Strengthen the Spleen

The Spleen is the root of postnatal Qi and the primary organ for processing dampness. A strong Spleen prevents damp-heat from forming:

• Eat cooked, warm foods: Lightly steamed or stir-fried vegetables, soups, and congee. Avoid raw and cold foods.
• Incorporate Spleen tonics: Chinese yam, millet, red dates, and lotus seed all support Spleen function. See our Spleen TCM functions guide.
• Avoid damp-heat generating foods: Greasy, fried foods, alcohol, excessive sweets, and spicy foods all contribute to damp-heat. Reduce or avoid during Guyu.
• Regular meal times: The Spleen thrives on routine. Eat at consistent times, with the largest meal at midday when Spleen energy is strongest.

3. Care for the Skin

Damp-heat often manifests through the skin. To support skin health during Guyu:

• Internal approach: Eat mung beans, winter melon, and green tea to clear heat and drain dampness from within. The skin reflects internal conditions — clear the inside, and the outside will follow.
• External approach: Keep skin clean and dry. Avoid heavy, oil-based skincare products. Use light, water-based moisturizers.
• Gentle sweating: Exercise to a light sweat helps vent damp-heat through the pores in a controlled way. Avoid excessive sweating, which depletes Qi.
• Avoid hot, humid environments: Saunas and steam rooms may feel good but can worsen damp-heat. Opt for fresh air and moderate exercise.

4. Press Damp-Heat Clearing Points

• Zusanli (ST36): Below the knee, on the outer side of the shin. The most important point for strengthening the Spleen and supporting digestion. Press for 2 minutes per leg.
• Yinlingquan (SP9): Below the knee, on the inner side of the shin, in the depression below the knee. This is the key point for draining dampness. Press for 1 to 2 minutes per leg.
• Quchi (LI11): At the outer end of the elbow crease. Clears heat and supports skin conditions. Press for 1 minute per arm.

5. Practice Gentle Exercise and Proper Rest

• Gentle exercise: Brisk walking, Qigong, or light hiking to move Qi and promote gentle sweating. Avoid excessive sweating that depletes Qi and Yin.
• Morning exercise: Exercise in the morning when the air is cooler and fresher. Avoid exercising during the hottest, most humid parts of the day.
• Adequate rest: Damp-heat can cause fatigue. Rest when tired, and avoid pushing through exhaustion. A short midday nap (15 to 30 minutes) supports the Spleen and Heart.

Contraindications and Precautions

• Skin conditions: If you have eczema, psoriasis, or chronic acne, follow your dermatologist's treatment plan. TCM practices are complementary only.
• Chronic digestive disorders: If you have IBS, Crohn's disease, or ulcerative colitis, consult your gastroenterologist before making significant dietary changes.
• Cold constitution: If you tend toward cold and deficiency (pale complexion, cold hands and feet, loose stools), use mung beans and cooling foods in moderation. Balance them with warming foods like ginger and red dates.
• Pregnancy: Some acupressure points are contraindicated during pregnancy. Consult a qualified practitioner.
• Mung bean caution: Mung beans are cooling. In large quantities or for those with weak digestion, they can cause bloating. Cook them thoroughly and combine with warming grains.

References and Classical Sources

• Huangdi Neijing (Yellow Emperor's Inner Canon), circa 200 BCE — Suwen Chapter 5: Dampness and heat correspondences. Suwen Chapter 74: Damp-heat pathology and treatment principles.
• Bencao Gangmu by Li Shizhen, 1578 — Documents mung beans as clearing heat and detoxifying, coix seed as draining dampness and strengthening the Spleen, winter melon as clearing heat and promoting urination.
• Shanghan Lun by Zhang Zhongjing, circa 220 CE — Contains formulas for damp-heat, including Yin Chen Hao Tang (Artemisia Capillaris Decoction) for damp-heat jaundice.

Related Tools and Resources

• Dampness-Removing Foods — Complete guide to foods that drain dampness and support the Spleen.
• Spleen TCM Functions — The Spleen's role in digestion, fluid metabolism, and dampness processing.
• Mung Bean Congee — How to make the classic damp-heat-clearing congee.
• TCM Constitution Quiz — Check if you tend toward a damp-heat pattern.

The Bottom Line

Guyu is the bridge between spring and summer. The warming temperatures and abundant rainfall that nourish the grain also create the conditions for damp-heat in the body. This compound pathogen — sticky, heavy, and hot — can manifest as skin problems, digestive sluggishness, urinary issues, and persistent fatigue. But Guyu also offers its own remedy: the foods that grow in this season are precisely those that clear heat and drain dampness. Mung beans, coix seed, and winter melon are nature's damp-heat-clearing pharmacy. Strengthen the Spleen with warm, cooked, easily digestible foods so it can process dampness efficiently. Care for your skin from the inside out by keeping your internal environment clean. Exercise gently to promote proper sweating without depleting Qi. As the last solar term of spring, Guyu is your final opportunity to clear what has accumulated through the season and prepare the body for the heat of summer. Honor the grain rain — let it nourish you, not burden you.