Juncus Effusus Crucian Carp Soup: Traditional Lingnan Medicinal Recipe

Juncus Effusus (Common Rush) and Crucian Carp Soup — A Medicinal Diet Introduction

Introduction to Medicinal Cuisine

Lampwick (Juncus effusus, Rush Pith) and Crucian Carp (Carassius auratus) soup is a traditional Lingnan-region medicinal food for clearing heat and promoting urination to resolve dampness. The main ingredients are Juncus effusus (Rush Pith) and Carassius auratus (Crucian Carp), supplemented with fresh ginger, tangerine peel, and other ingredients, slow-cooked into a broth. Juncus effusus is slightly cold in nature, sweet and bland in flavor, and enters the Heart (HT), Lung (LU), and Small Intestine (SI) meridians. It excels at clearing heart fire, promoting urination, and treating stranguria. Carassius auratus is neutral in nature and sweet in flavor; it strengthens the Spleen, resolves dampness, harmonizes the Middle Burner, and opens the appetite. When combined, the slightly cold nature of Juncus effusus is moderated, while the Spleen-strengthening and dampness-resolving effects are enhanced. This makes the soup moistening and cooling without being chilling, and tonifying without causing stagnation.

This medicinal dietary recipe has long been circulated among the people, especially suitable for consumption during the transition from spring to summer or during periods of heavy damp-heat. The soup is milky white in color, with a refreshing aroma and a naturally sweet taste. It is not only a delicious soup but also a gentle dietary therapy remedy. Many families in the Lingnan region prepare this as a daily health‑promoting soup to alleviate discomfort caused by summer‑heat or dampness.

Efficacy of Medicinal Diet

The main effects of Juncus Effusus and Crucian Carp Soup can be summarized as “clearing the heart and descending fire, strengthening the spleen and draining dampness, promoting urination and relieving restlessness.” Juncus Effusus (Dengxincao) clears heat from the Heart Meridian (HT), offering significant relief for symptoms such as irritability, insomnia, oral ulcers, and scanty dark urine caused by heart fire flaring upward. Crucian Carp (Jiyu) fortifies the spleen, opens the stomach, and promotes urination to reduce edema. Together, one herb clears while the other tonifies, allowing pathogenic damp-heat to be expelled through urination while simultaneously protecting the qi of the spleen and stomach.

Modern nutritional science has also confirmed that crucian carp (Carassius auratus) is rich in high-quality protein, various amino acids, and trace elements, making it easy to digest and absorb, and thus suitable for recovery after illness or postpartum conditioning. Common rush (Juncus effusus) contains multiple flavonoids, which have certain anti-inflammatory and diuretic effects. Therefore, this medicated diet also holds auxiliary therapeutic value in improving conditions such as dysuria, edema, and damp-heat diarrhea and dysentery.

The Role of Traditional Chinese Medicine

From the perspective of TCM herbal pairing theory, the combination of *Juncus effusus* (common rush) and *Carassius auratus* (crucian carp) embodies the formula principle of “clearing the upper and freeing the lower, tonifying the middle while concurrently clearing.” Heart Fire Blazing often manifests as irritability, insomnia, and painful astringent urination. *Juncus effusus*, light and upward in nature, excels at clearing heart fire and guiding heat downward. *Carassius auratus* enters the Spleen, Stomach, and Large Intestine meridians, tonifies the middle *jiao*, and transforms water-dampness, thereby preventing *Juncus effusus* from excessively cooling and damaging the Stomach.

In addition, the decoction is often accompanied by Shengjiang (Zingiber officinale, Ginger) and Chenpi (Citri Reticulatae Pericarpium, Tangerine Peel). Shengjiang, pungent and warm, disperses cold, harmonizes the Middle and stops vomiting, thereby moderating the cold nature of Dengxincao (Medulla Junci, Rush Pith). Chenpi regulates qi and strengthens the Spleen, dries dampness and transforms phlegm, enhancing the Crucian Carp (Carassius auratus) effect of strengthening the Spleen and dispelling dampness. The entire formula has a balanced nature, primarily acting on the Heart (HT), Spleen (SP), and Small Intestine (SI) meridians. It can both clear fire from the Upper Jiao and drain dampness from the Lower Jiao, allowing the pathogenic Damp-Heat to be expelled without damaging the Righteous Qi.

Analysis of the Mechanism of Action

The primary active constituents of *Juncus effusus* (Common Rush) include juncusin, flavonoids, and phenolic acids, which exhibit clear diuretic and anti-inflammatory effects. The retinol, vitamin D, calcium, and phosphorus in *Carassius auratus* (Crucian Carp) help repair the intestinal mucosa and improve digestive function. Their synergistic action achieves the triple effect of “clearing heart fire, promoting urination, and strengthening the spleen and stomach,” making it especially suitable for various sub-health conditions arising from internal accumulation of damp-heat.

Suitable Population

This medicinal diet is particularly suitable for the following groups of people:

First, Heart Fire Hyperactivity pattern. Manifestations include irritability, insomnia with excessive dreaming, mouth and tongue sores, dark yellow urine, and a red tip of the tongue. This condition is often exacerbated by work stress, staying up late, or consuming spicy foods. Juncus effusus (rush pith) clears the heart and reduces fire, combined with Carassius auratus (crucian carp) to nourish yin, effectively alleviating the above symptoms.

Second, for those with Dampness-Heat Accumulation. Common symptoms include heaviness in the head and body, epigastric and abdominal distension and fullness, poor appetite, difficult urination or sticky, unpleasantly sloppy stools, and a yellow, greasy tongue coating. This soup can fortify the spleen and disinhibit dampness, promote urination, and help the body expel excess dampness.

Third, for those suffering from thirst and irritability due to Summer-Heat Dampness in summer. In summer, the weather is hot and rainy, making the human body susceptible to Summer-Heat Dampness pathogens, manifesting as fever with scanty sweating, thirst, restlessness, scanty dark urine. Medulla Junci (Common Rush) simmered with Crucian Carp soup is abundant in fluid, which not only replenishes water but also clears Summer-Heat and alleviates thirst.

Contraindicated Populations

Although Juncus effusus (common rush) and crucian carp soup has mild medicinal properties, the following groups of people should still consume it with caution:

I. For those with Spleen and Stomach Deficiency Cold. If the patient typically presents with aversion to cold, cold hands and feet, loose stools, poor appetite, and a pale, enlarged, and tender tongue, this indicates insufficiency of Spleen and Stomach yang qi. The slightly cold nature of Juncus effusus (Common Rush) may aggravate the deficiency cold symptoms. It is recommended to reduce the dosage or add more Zingiber officinale (Ginger) and Ziziphus jujuba (Red Jujube) to warm the Middle Jiao.

II. Pregnant and breastfeeding women. *Juncus effusus* (Common Rush) has a diuretic effect that may affect electrolyte balance, and its safety during pregnancy has not been fully studied. It is recommended to use it under the guidance of a physician. Breastfeeding women should also use it with caution, as it may affect the infant through breast milk.

3. For patients with Kidney Deficiency and frequent urination: individuals with nocturia, soreness and weakness of the lower back and knees, and clear, copious urination already have Kidney Qi Not Secure. They should avoid using diuretic substances to prevent exacerbating symptoms.

4. For those with fish allergy. It should be contraindicated for individuals allergic to crucian carp or freshwater fish. Alternatively, lean meat or pork ribs may be used as a substitute for crucian carp.

Ingredient Formula Proportions

The following is the exact ratio for 2-3 servings:

• Main ingredient: 1 fresh live crucian carp (Carassius auratus, about 300–400 grams, scaled, gutted, gills removed, washed and set aside)
• Supplementary ingredient: 15–20 g dry Common Rush (Juncus effusus), purchased from a pharmacy, tied into small bundles or packed in a gauze bag.
• Seasonings: 3–4 slices of Fresh Ginger (Zingiber officinale, Sheng Jiang) (approx. 10 g), 1 segment of Dried Tangerine Peel (Citrus reticulata, Chen Pi) (approx. 3 g, pre-soaked until soft and white pith scraped off), 2 segments of Scallion (Allium fistulosum, Cong) (approx. 10 g)
• Season with appropriate amount of salt (approximately 3–4 grams, added at the end) and 1 tablespoon cooking wine (approximately 5 ml, used to remove fishy odor).
• Water: It is recommended to use purified or mineral water, with a total volume of approximately 1500–1800 ml.

Cooking Method

Step 1: Prepare the ingredients. Clean the crucian carp (Carassius auratus) thoroughly, pat dry inside and out with a kitchen paper towel, make three diagonal slashes on each side of the fish, and rub with a small amount of cooking wine and salt, then marinate for 10 minutes. Quickly rinse the rush pith (Juncus effusus, Medulla Junci) under running water to remove surface dust, then tie it into a small bundle or wrap it in a gauze bag. Slice the fresh ginger (Zingiber officinale). Soak the dried tangerine peel (Citri Reticulatae Pericarpium) until soft, then scrape off the white pith and set aside.

Step 2: Pan-fry the crucian carp (Carassius auratus). Take a flat-bottomed pan or non-stick skillet, heat it up, then pour in a small amount of cooking oil (about 5 ml). When the oil reaches about 70% heat (moderately hot), place the crucian carp into the pan. Fry over medium heat until both sides are lightly golden and the fish is set. This step removes the fishy odor, helps the soup turn milky white more easily, and enhances the aroma.

Step 3: Simmer the soup. Place the pan-fried crucian carp (Carassius auratus) into a clay pot or soup pot, add sufficient hot water (approximately 1500 ml), then add Juncus effusus (common rush), fresh ginger slices, Citri Reticulatae Pericarpium (tangerine peel), and scallion segments. Bring to a boil over high heat, skim off any foam, then reduce to low heat, cover, and simmer for 40–50 minutes until the broth turns milky white and the fish becomes tender.

Step 4: Seasoning and finishing. Remove the scallion segments and the bundle of Common Rush (Juncus effusus) (or the whole tied bunch) before turning off the heat. Add an appropriate amount of salt to taste, stir evenly, and serve. Note that salt must be added at the very end; adding it too early will cause the fish to become tough and the fresh flavor to be lost.

Drinking Tips

1. Consuming both the soup and the meat yields better results. Many people only drink the soup and discard the meat, but fish meat is rich in high-quality protein and various nutrients. Eating them together allows for a more comprehensive absorption of the tonifying effects of the medicated diet. It is recommended to separate the fish meat and dip it in a small amount of soy sauce or ginger-vinegar sauce before eating.

2. The best time to consume this soup is in the morning or afternoon. From 9:00 to 11:00 AM, the Spleen Meridian (SP) is most active; from 3:00 to 5:00 PM, the Bladder Meridian (BL) is most active. Drinking this soup during these periods helps fortify the spleen and promote diuresis respectively, yielding better results. It is not recommended to drink large amounts after 9:00 PM, as it may cause frequent nocturia and disturb sleep.

3. It is advisable to consume 2–3 times per week, and not for more than two consecutive weeks. Moderation is essential in medicinal dietary therapy. Although Juncus effusus (Common Rush) has the effect of clearing Heat, long-term or excessive use may impair Yang Qi. A general recommendation is to take it 2–3 times per week for 1–2 weeks, then pause for one week before deciding whether to continue based on changes in the individual’s constitution.

4. The ingredients can be flexibly adjusted according to constitution. If the Cold pattern is more pronounced, increase ginger to 6–8 slices, or add 3–5 pitted red dates (Ziziphus jujuba); if the Damp-Heat pattern is stronger, add 15 g of rice bean (Vigna umbellata) or 10 g of coix seed (Coix lacryma-jobi) to cook together to enhance the dampness-draining effect. After adjustment, the total simmering time should remain unchanged.

5. Fish bones must be thoroughly removed. Crucian carp (Carassius auratus) have numerous and fine bones, especially in the belly and tail areas. When serving to children or the elderly, carefully remove all fish bones to ensure safe consumption. Alternatively, mash the fish meat with a spoon, strain it, and consume only the minced meat together with the soup.