Fěi Zǐ (榧子) — Torreya seed / Chinese nutmeg yew nut

On this page

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

1. Overview

Fěi Zǐ (榧子) — the seed of Torreya grandis, the Chinese nutmeg yew — is one of the gentlest and most broadly active herbs in the “Herbs that expel parasites” (Sha Chong Yao) category of the Chinese Materia Medica. It addresses all four of the principal intestinal helminths — roundworm, hookworm, tapeworm and pinworm — with a sweet, neutral, well-tolerated profile that is rare among anti-parasitic herbs. Beyond its parasitic role it also moistens the intestines (useful in constipation) and the Lung (used in dry cough). The seed is edible as a food (the “Chinese nutmeg yew nut”) as well as a herb. It is used in Chinese herbal medicine as a component of classical formulas and in tailored prescriptions.

I prescribe Fěi Zǐ as part of bespoke herbal formulas from pharmaceutical-grade granules sourced from Sun Ten in Taiwan. Online consultations are available for patients who cannot attend my clinic in person.

2. Properties

3. Actions and indications

Principal actions

1. Kills parasites — broad spectrum: hookworm, roundworm, tapeworm and pinworm
2. Moistens the intestines and relieves constipation
3. Moistens the Lung and stops dry cough (a secondary use)

Indications

1. Hookworm infection — particularly responsive to Fei Zi
2. Roundworm, pinworm and tapeworm infections
3. Constipation, particularly dry constipation in the elderly or with Yin deficiency features
4. Dry cough from Lung Yin deficiency (less commonly used for this; secondary action)

4. Key formulas containing Fěi Zǐ

Fěi Zǐ is most often used as a single herb (typically roasted) or in simple combinations. Classical formulas where it appears include:

• Hua Chong Wan (Transform Worms Pill) — broad-spectrum anti-parasitic combination
• Modified San Huang Tang with Fei Zi added for parasitic clearance

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

5. Modern research

Torreya grandis seeds contain torreyanic acid, a unique tropolone alkaloid, along with fatty acid components and tannins. Modern Chinese clinical research has confirmed efficacy particularly against hookworm and tapeworm, with documented expulsion rates comparable to conventional anthelmintic treatment in some series. The seed’s neutral nature and good gastrointestinal tolerability make it a useful first-line choice when a gentler herbal approach is appropriate.

6. Incompatibilities

Fěi Zǐ 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).

7. Cautions and contraindications

Fei Zi is one of the gentlest anti-parasitic herbs and is well-tolerated at standard doses. The principal cautions are: avoid in patients with active diarrhoea (the intestine-moistening action can worsen it) and in pregnancy. Excessive doses may cause mild gastrointestinal upset.

Pattern contraindications

Avoid in patients with Spleen deficiency with loose stools or active diarrhoea; the moistening action is unhelpful in these patterns.

Modern drug interactions

No significant drug interactions documented at standard therapeutic doses. As with all herbal treatments, tell your GP and your herbalist about all medications you are taking.

8. Sustainability note

Torreya grandis is listed as Endangered (EN) on the IUCN Red List of Threatened Species in its wild form. The herb used in modern Chinese herbal practice and the edible nut form sold across East Asia are typically cultivated from established commercial orchards rather than wild-harvested; pharmaceutical-grade granules from regulated suppliers including Sun Ten in Taiwan are sourced from cultivated material. Wild-harvested Fei Zi is not used in reputable modern practice.

9. Treatment at my clinic

I prescribe Fěi Zǐ as part of tailored herbal formulas for parasitic infections (see my intestinal parasites article) and occasionally for constitutional dry constipation patterns. Every prescription is individually formulated following a full TCM assessment.

I see patients in person at my clinic in Wokingham, Berkshire. Online Chinese herbal medicine consultations are available throughout the UK and internationally. Visit the prices page for consultation fees.

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