Yù Mǐ Xū (玉米须) — Corn silk

On this page

1. Overview
2. Properties
3. Actions and indications
4. Key formulas
5. Modern research
6. Incompatibilities
7. Cautions and contraindications
8. Treatment at my clinic

1. Overview

Yù Mǐ Xū (玉米须) — Stigma Maydis, the dried styles and stigmas of Zea mays — is known in English as corn silk. It belongs to the category of Herbs that drain Dampness in the Chinese Materia Medica and is used in traditional Chinese medicine (TCM) as a mild, bland diuretic within Chinese herbal medicine prescriptions.

Maize reached China from the Americas in the sixteenth century and corn silk was absorbed into the materia medica during the Qing dynasty, making it one of the later additions to the Chinese pharmacopoeia. It is unusual among the damp-draining herbs for being neutral in temperature and genuinely gentle, which is why it is tolerated over long courses where stronger diuretics are not.

I prescribe Yù Mǐ Xū as part of bespoke herbal formulas from pharmaceutical-grade granules sourced from Sun Ten in Taiwan. Herbs are always combined with other herbs selected to match the patient’s individual TCM pattern. Online consultations are available for patients who cannot attend my clinic in person.

2. Properties

3. Actions and indications

Principal actions

1. Promotes urination and drains Dampness — the bland flavour leaches fluid downwards
2. Reduces oedema and swelling
3. Clears Damp-Heat from the Liver and Gallbladder; reduces jaundice
4. Clears Damp-Heat from the Bladder

Indications

1. Oedema with scanty urination, particularly of the lower limbs
2. Damp-Heat lin syndromes with painful, scanty, dark urination
3. Jaundice and Gallbladder Damp-Heat with a bitter taste and right-sided rib fullness
4. Urinary stones from Damp-Heat accumulation
5. Hypertension accompanying Damp accumulation, as a supporting herb

Yù Mǐ Xū is a mild herb and is rarely the chief herb in a prescription. It is most often used as a deputy or assistant to strengthen the damp-draining action of a formula without adding thermal bias, or in large single-herb doses as a folk decoction.

4. Key formulas containing Yù Mǐ Xū

Yù Mǐ Xū is a later addition to the materia medica and does not appear in the classical Han and Tang dynasty formulas. It is used principally as a modification to existing damp-draining formulas rather than as a constituent of a named classical prescription, and appears in modern Chinese hospital formularies for oedema and jaundice.

See the full Chinese herbal medicine formula directory for detailed information on all 332 classical formulas.

5. Modern research

Stigma Maydis contains flavonoids (notably maysin), potassium salts, saponins, sterols, allantoin and volatile oils. Research has examined diuretic, antihypertensive, hypoglycaemic, anti-inflammatory and antioxidant activity, and the potassium content is thought to contribute to the diuretic effect observed in animal studies. Much of the available evidence is preclinical, and well-designed human trials remain limited — the herb is best regarded as traditionally used and pharmacologically plausible, with its clinical value in any specific condition not yet established.

6. Incompatibilities

Yù Mǐ Xū (玉米须) Corn silk is not listed in either of the two classical incompatibility texts — Shi Ba Fan (Eighteen Antagonisms) or Shi Jiu Wei (Nineteen Mutual Inhibitions). As with every Chinese herb it should be prescribed only as part of a balanced formula by a registered Chinese herbalist (RCHM), who will check for interactions with any other herbs and prescription medications you are taking.

7. Cautions and contraindications

Traditionally cautioned in pregnancy. Use with care in patients taking diuretic, antihypertensive or hypoglycaemic medication, where the actions may be additive. Avoid prolonged use in Yin deficiency with dryness, as sustained draining further depletes fluids.

Pattern contraindications

Not indicated where there is no Dampness. Prolonged draining in a depleted patient consumes Yin and Body Fluids.

Modern drug interactions

May potentiate loop and thiazide diuretics, antihypertensives and hypoglycaemic agents. Tell your doctor if you take any of these.

Important: Chinese herbs should always be prescribed by a fully qualified herbalist who is a member of the Register of Chinese Herbal Medicine (RCHM). Never self-prescribe or self-administer Chinese herbs without professional guidance. Dr (TCM) Attilio D’Alberto is a member of the RCHM with over 25 years of clinical experience.

8. Treatment at my clinic

I prescribe Yù Mǐ Xū as part of tailored herbal formulas where Dampness and fluid accumulation form part of the pattern. Every prescription is individually formulated following a full TCM assessment and adjusted throughout treatment as the pattern responds.

Corn silk is also used as a domestic beverage in Chinese households, prepared quite differently from a herbal prescription — see corn silk tea for the kitchen preparation, which is a food-therapy measure rather than a prescribed treatment.

Online Chinese herbal medicine consultations are available throughout the UK and internationally. Visit the prices page for consultation fees.

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Prefer to be treated from home? Chinese herbal medicine online consultations are available throughout the UK and worldwide. After a full video consultation, Dr (TCM) Attilio D'Alberto formulates a bespoke herbal prescription and posts your Chinese herbs directly to your door.