Watercress, Preserved Duck Kidney and Pork Bone Soup

Why people make this soup

After indulging in a few too many lychees — that deliciously warming fruit — the familiar telltale signs can appear: a dry, scratchy throat and a slight feverish feeling that the Chinese tradition calls “internal heat.” Rather than reaching for something cold and harsh, this gentle, nourishing soup is a traditional remedy the whole family can enjoy. It is clear, slightly sweet, and genuinely cooling without being aggressive.

Watercress is a leafy green that traditional Chinese food therapy considers cool in nature, associated with moistening the lungs and easing dry coughs. Combined with the mild, savoury depth of preserved duck kidney, which is traditionally valued for nourishing yin and supporting the spleen, this is a soup that soothes rather than shocks.

Who it suits / who should be cautious

• Well suited to adults and children feeling dry-throated, mildly overheated from eating warming foods, or dealing with a dry cough with yellow phlegm
• Pregnant women may drink this soup according to a reader Q&A with Bro Niu
• Those with a cold constitution or a cough that worsens at night with thin, clear phlegm (a “cold-type cough”) should be cautious — watercress is cooling; adding extra ginger slices helps moderate this
• If you have diabetes, note that honey dates are sweetened and may affect blood sugar; consider substituting with figs (wu hua guo)

Why these ingredients (the food-therapy logic)

• Watercress (xi yang cai): In traditional food therapy, it is considered cool and slightly bitter, associated with clearing lung heat, easing dry coughs, and supporting urinary flow
• Preserved duck kidney (chen ya shen): Dried and aged duck kidneys are traditionally used to nourish yin, strengthen the spleen, and add a gentle savoury flavour to soups
• Pork bones: Provide body and richness to the broth; traditionally associated with supporting the kidneys and bones
• Honey dates (mi zao): Help balance the slight bitterness and cool nature of the watercress, making the soup more palatable and adding a mild moistening quality; note that they are sugar-cured, so figs are a healthier substitute for those watching sugar intake
• Ginger (sheng jiang): A warming counterbalance that helps temper the cooling nature of the watercress

Ingredients (4–5 bowls)

Ingredient	Amount	Notes
Watercress	600 g	Soak and rinse thoroughly
Pork bones	450 g	Blanched to remove impurities
Preserved duck kidney	2 pieces	Soaked and rinsed
Honey dates	2 pieces	Or substitute with 4 dried figs
Fresh ginger	2 slices

Method

1. Blanch the pork bones and duck kidneys in boiling water for a few minutes, then drain and rinse — this removes any off-flavours and ensures a clear broth.
2. Soak the watercress in water and rinse it well to clean thoroughly.
3. Add the pork bones, preserved duck kidneys, honey dates, and ginger slices to a pot with 10 bowls of cold water (approximately 2 litres). Bring to a full boil over high heat.
4. Once boiling, add the watercress to the pot.
5. Reduce to a gentle simmer and cook for about 1.5 hours. Serve the soup and enjoy the tender vegetables alongside.

Bro Niu’s tips

Always add the watercress into boiling water — if you start it in cold water, the soup can develop a bitter, astringent taste. This soup is suitable for the whole family, young and old. For anyone with dry, sluggish bowels or constipation, try adding a carrot and a few dried figs to the pot — they make the soup even more helpful for relieving that kind of discomfort. You can also add raw fish or carrot as variations.

Community questions answered (selected)

• Q (Yuki): Can pregnant women drink this soup? Bro Niu: Yes, pregnant women can drink this soup.

• Q (Fanny): Can you drink this if you have a cough? Bro Niu: If you cough more during the day and your phlegm is yellow and thick, this soup is suitable. But if you have a night-time cold-type cough, it is not appropriate.

• Q (reader): What if I am in Australia and can only find fresh duck kidneys, not preserved ones? Bro Niu: Fresh duck kidneys are fine as a substitute, or you can simply use carrot instead.

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Published July 1, 2015 · Adapted and translated for Nourilo from a traditional home-kitchen recipe. Approx. 3 min read.