Yi Yu 衣鱼 — Chinese Herbal Medicine

Yi Yu (衣鱼) At a Glance

• Herb: Yi Yu
• Chinese name: 衣鱼 (Yi Yu)
• Latin name: Lepisma saccharina
• Nature: Warm
• Taste: Salty
• Meridian: Liver
• Category: Promotes blood circulation and eliminates masses

Yi Yu (衣鱼) is the dried body of the silverfish insect, Lepisma saccharina, a minor but historically documented animal substance in the Chinese materia medica. Warm in nature and salty in taste, it enters the Liver channel, where its primary action is to break up blood stasis, resolve fixed accumulations, and open obstructed passages. It is employed in gynecological stagnation, abdominal masses, and select urinary and skin disorders where stasis and binding are the root pathology.

Actions & Therapeutic Effects

• Promotes blood circulation and dispels blood stasis
• Dissolves masses and breaks up fixed accumulations
• Opens obstructions in the Liver channel
• Frees urination and relieves strangury
• Resolves skin lesions and relieves persistent itching

Clinical Applications in TCM

• Amenorrhea and dysmenorrhea from blood stasis — combine with Tao Ren (桃仁), Hong Hua (红花), and Chuan Xiong (川芎)
• Fixed abdominal masses and hypochondriac pain — pair with E Zhu (莪术) and San Leng (三棱)
• Urinary obstruction and painful strangury — use with Hua Shi (滑石) and Mu Tong (木通)
• Chronic scabies, skin nodules, and intractable pruritus — apply powdered form topically or take internally with Ku Shen (苦参)
• Post-partum blood stasis with lower abdominal pain — combine with Yi Mu Cao (益母草) and Pu Huang (蒲黄)

Precautions & Safety

• Dosage: 1–3 g in decoction; 0.3–1 g as ground powder taken with warm water or applied topically
• Contraindicated during pregnancy; use with caution in patients with blood deficiency without concurrent stasis; avoid prolonged use without clinical reassessment

Classical TCM Formulas

• Ge Gen decoction: Yi Yu (kudzu starch) is used as the thickener for medicinal pastes.
• Ge Gen Tang (葛根汤) uses Ge Gen root; Yi Yu is the purified starch by-product.
• Kudzu starch is a common East Asian food ingredient in Japanese (kuzukiri) and Chinese cuisine.

Herb Combinations

• Yi Yu (葛粉) + Ge Gen (葛根): the starch supports the root’s exterior-releasing action — Yi Yu is the food-grade starch, Ge Gen is the medicinal root.
• Yi Yu (葛粉) as a food: kudzu starch paste (葛粉糕) for Summerheat thirst and acute dysentery.
• Yi Yu (葛粉) + Gan Cao (甘草) + honey: the demulcent combination for dry throat and thirst.

Pharmacology & Research

Chitin: structural polysaccharide of the exoskeleton; associated with immunomodulatory and mild anti-inflammatory activity.
Proteins and enzymes: bioactive peptides that may contribute to fibrinolytic and tissue-remodelling effects.
Lipids and fatty acids: provide emollient properties relevant to topical applications for skin conditions.

Classical Descriptions

• “Yi Yu enters the blood aspect; it disperses stagnant accumulations, opens the waterways, and treats obstruction of menstruation and fixed masses below the umbilicus.” — *Ben Cao Gang Mu* (本草纲目, Li Shizhen, 1596), Insect Section