Bu Gu Zhi and Pork Kidney Soup: A Classic Kidney Tonic

Introduction to Medicinal Diet

Bu Gu Zhi (Psoralea corylifolia) and Pork Kidney Soup is a traditional Chinese medicinal diet with a long history, traceable to dietary therapy texts from the Tang and Song dynasties. This medicinal soup features Bu Gu Zhi (Psoralea corylifolia) and pork kidney as core ingredients, combined with various warming and tonifying herbs, slow-simmered to perfection. The broth is milky white and clear, with a rich, mellow, and slightly sweet aroma. It tastes warm and smooth on the palate, preserving the tenderness of the pork kidney while absorbing the essence of the herbs—a classic soup that harmoniously blends flavor and health benefits.

In folk medicine, the *Psoralea corylifolia* and Pig Kidney Soup has long been hailed as a “kidney fuel station,” commonly used to regulate various discomforts caused by Kidney Deficiency. Its formula, refined over centuries, is artfully combined—tonifying without producing dryness, warming without being harsh—making it especially suitable as a daily health tonic for middle-aged and elderly individuals, as well as those with a Deficiency-Cold constitution. Modern nutritional science also confirms that this soup is rich in protein, calcium, zinc, and a variety of vitamins, significantly contributing to the enhancement of immune function.

Efficacy of Medicinal Diet

The primary effect of *Buguzhi Zhuyu Tang* (Psoralea corylifolia and pig kidney soup) is to warm and tonify kidney yang, secure essence, and reduce urination. It is beneficial for symptoms of kidney yang deficiency such as soreness and weakness of the lower back and knees, aversion to cold with cold extremities, frequent nocturia, and clear, copious urine. Additionally, it effectively alleviates issues due to kidney qi not consolidating, such as spermatorrhea, involuntary emission, and chronic diarrhea, helping to restore normal kidney function.

In addition to regulating the Kidney system, this soup also excels at strengthening sinews and bones. Pig kidney is rich in high-quality protein and trace elements, capable of nourishing bone marrow and fortifying the lower back and knees; *Psoralea corylifolia* (Malaytea Scurfpea fruit) promotes calcium absorption and deposition, playing an active role in preventing and alleviating osteoporosis as well as lower back and leg pain. Regular and moderate consumption can invigorate vitality, ensure a steady gait, and slow the aging process.

Special value for male health

For men, Psoralea and Pig Kidney Soup also serves as a supplementary aid for enhancing reproductive function and improving sexual vitality. The Kidney stores essence and governs reproduction. By warming and supplementing Kidney yang, this soup effectively increases sperm motility and count. It provides a gentle and sustained regulating effect for conditions such as impotence, premature ejaculation, and loss of libido caused by Kidney deficiency.

Functions of Traditional Chinese Medicine

From the perspective of Traditional Chinese Medicine (TCM), Psoralea corylifolia (Fructus Psoraleae, common English name: Malaytea Scurfpea) has an acrid and bitter flavor with a warm nature, and is attributed to the Kidney (KI) and Spleen (SP) meridians. Its functions include tonifying the Kidney and assisting Yang, absorbing Qi to relieve panting, and warming the Spleen to stop diarrhea. According to the *Bencao Gangmu* (Compendium of Materia Medica), it “treats Kidney diarrhea, unblocks the Vital Gate (Mingmen), warms the Elixir Field (Dantian), and astringes the essence and spirit,” making it an essential herb for tonifying the Kidney. Pig kidney, the kidney of *Sus scrofa domestica*, has a sweet and salty flavor with a neutral nature, and enters the Kidney meridian. It tonifies Kidney Qi, unblocks the Bladder, dissipates accumulations and stagnations, and relieves wasting-thirst (*xiao ke*). Following the principle of “using the organ to nourish the organ,” its effects are potent and focused.

The combination of the two forms a classic “drug-catalyst” model: Psoralea corylifolia (Bu Gu Zhi) warmly fortifies kidney yang, while pig kidney nourishes kidney yin—one yang, one yin, mutually supporting each other. Additionally, the addition of acrid-warm herbs such as Zingiber officinale (ginger) and Allium fistulosum (scallion white) not only removes fishy smell and enhances flavor, but also moves qi and disperses cold, assisting the medicinal power to reach the affected area directly. The entire soup is warming without being drying, tonifying without being cloying, embodying the TCM principle of “seeking yang within yin and seeking yin within yang” in formula compatibility, so that kidney yang is supplemented without harming yin, and kidney yin is nourished while yang qi naturally generates.

Suitable for

This decoction is particularly suitable for middle-aged and elderly individuals, especially those presenting with Kidney deficiency symptoms such as soreness and weakness of the lower back and knees, weakness in walking, frequent nocturia, and aversion to cold with fear of cold. For patients with lumbar muscle strain or lumbar disc herniation caused by prolonged physical labor or prolonged sitting at a desk, consuming this decoction can help alleviate lumbar discomfort and promote tissue repair. In addition, individuals experiencing debility after childbirth or illness, as well as those with depletion of primordial qi, are also appropriate candidates for using this decoction to tonify primordial qi and restore physical strength.

In specific seasons, such as the cold of winter, the body’s yang qi is stored internally, making it an ideal time to tonify the kidney and nourish the essence. Consuming Psoralea (补骨脂, Psoralea corylifolia) and Pork Kidney Soup during this period, leveraging the seasonal advantage, can maximize the warming and tonifying effects of the medicinal diet, thereby enhancing the body’s ability to resist Cold pathogen. For issues such as male reproductive function decline, reduced sperm quality, and low libido, regular consumption under the guidance of a TCM physician can also yield favorable regulatory effects.

Contraindicated Populations

Those with yin deficiency with effulgent fire (Yin Deficiency Fire Hyperactivity) should use this medicated diet with caution. This pattern typically manifests as heat in the palms and soles, dry mouth and throat, tidal fever and night sweats, red tongue with scant coating, and dry stools. If warming and tonifying substances are mistakenly taken, it is like adding fuel to the fire, aggravating the internal heat symptoms. Such individuals should select medicated diets that nourish yin and clear heat, such as Dendrobium and Ophiopogon Decoction (Shi Hu Mai Dong Tang).

Patients with Excess Heat Pattern and Damp-Heat Pattern should likewise avoid taking it. For example, symptoms such as common cold with fever, sore throat, cough with yellow phlegm, scanty dark urine, and a yellow greasy tongue coating indicate internal exuberance of Excess Heat or Damp-Heat. In such cases, tonifying would “close the door and detain the pathogen,” preventing pathogenic factors from dispersing externally and instead exacerbating the condition. Additionally, those allergic to pig kidney or *Psoralea corylifolia* (Buguzhi), as well as patients with hyperlipidemia or hypercholesterolemia, should also limit intake due to the high cholesterol content of pig kidney.

Ratio of Ingredients in the Formula

Pork kidney: 2 pieces (approx. 200 g). Psoralea corylifolia (Malaytea scruffpea fruit): 15 g. Juglans regia (English walnut kernel): 10 g. Lycium barbarum (Goji berry): 5 g. Zingiber officinale (Ginger): 3 slices (approx. 10 g). Allium fistulosum (Scallion white part): 2 sections (approx. 15 g). Cooking wine: 10 mL. Fine salt: appropriate amount (approx. 2 g). Water: 1500 mL.

The above ratio serves 2–3 people; adjust proportionally according to the number of persons. For Psoralea corylifolia (Fructus Psoraleae), it is recommended to select seeds that are black in color, plump, and free from insect damage. For pig kidney, fresh ones with a light red color and no foul odor are considered top quality. All medicinal herbs should be purchased from reputable Chinese herbal pharmacies to ensure quality and safety.

Preparation method

Step 1: Prepare the pig kidneys. Split the pig kidneys open and remove the white central part (the pelvis, which is the main source of any fishy smell). Rinse thoroughly under running water until no blood remains. Score the surface of the kidneys in a cross-hatch pattern, then cut into kidney flower pieces about 2 cm in size. Marinate with cooking wine and a pinch of salt for 10 minutes to remove any fishy odor and enhance the fresh flavor.

Step 2: Preprocess the medicinal herbs. Quickly rinse Psoralea corylifolia (buguzhi) under clean water to remove surface dust, then wrap in a gauze bag to prevent it from dispersing in the decoction and affecting the taste. Soak Juglans regia (walnut kernels) in warm water for 10 minutes, then peel off the skin (if not peeled, the decoction will have a slight bitterness). Slice fresh ginger (Zingiber officinale) and cut scallion white (Allium fistulosum) into sections; set aside.

Step Three: Blanching to remove fishy odor. Add enough clean water to a pot and place the marinated pork kidney slices into it. Bring to a boil over high heat and continue blanching for 1–2 minutes until the kidney slices change color and curl up. Immediately remove them and rinse off any foam with warm water. This step effectively eliminates the strong, fishy odor of the pork kidneys and is key to achieving a delicious, clear broth.

Step 4: Simmer into a soup. Place the blanched pig kidney, the wrapped *Fructus Psoraleae* (补骨脂), *Semen Juglandis* (walnut kernels), ginger slices, and scallion segments together into an earthenware pot or clay casserole. Add 1500 ml of water. Bring to a boil over high heat, then reduce to low heat and simmer gently for 40–50 minutes. When the soup turns milky white and fragrant, add *Fructus Lycii* (goji berries) and salt, and continue simmering for another 5 minutes before turning off the heat. Remove the medicinal herb sachet, ladle the soup into bowls, and serve.

Drinking Tips

1. Best Consumption Time: This soup has strong warming and tonifying effects. It is recommended to be taken warm during lunch or dinner, one small bowl (approximately 200 ml) each time. Avoid consuming on an empty stomach or before bedtime to prevent digestive discomfort or night heat and irritability. Drink 2–3 times per week for 4 consecutive weeks as one course of treatment.

2. Seasoning should be light: The essence of medicated diet soups lies in their original flavors; seasonings should be predominantly light, with salt used sparingly. Avoid heavy-flavored condiments such as soy sauce, monosodium glutamate (MSG), or chili peppers, as these can mask the subtle aroma of the herbs and increase the burden on the kidneys. A few grains of white pepper (Piper nigrum) may be added to the soup to warm the stomach, enhance aroma, and remove any fishy taste.

3. Incompatible Pairing Reminder: While consuming the soup of *Psoralea corylifolia* (Malaytea Scurfpea) and pork kidney, avoid simultaneously eating cold, moistening, and draining foods such as rape (Chinese rapeseed greens), pork blood, river snails, and persimmon (*Diospyros kaki*), as these may reduce the medicinal efficacy or cause gastrointestinal discomfort. If you are currently taking any Western or Chinese medications, it is recommended to consult a physician and allow a gap of at least 2 hours before consuming this soup to prevent antagonistic interactions between the medicinal properties.