Traditionally used for
- Dizziness
- Ears & hearing
- Digestion
- Urinary & fluids
- Pain & joints
- Energy & fatigue
Cautions & contraindications
- Allergy risk
- Toxic — professional use only
☯ TCM Properties
Nourishes Yin, subdues Yang and nourishes the Liver and Kidneys; Stops bleeding, dissipates Blood Stasis and resolves swelling; Calms the fetus
Traditional Chinese Uses
Yu Biao Jiao (fish maw isinglass), the dried swim bladder of large croakers such as Nibea albiflora, is a nourishing tonic. Sweet and neutral, entering the Liver, Kidney and Stomach, it enriches Kidney essence and Yin, subdues ascendant Liver Yang, benefits the Liver and Kidneys, stops bleeding and dissipates Blood stasis to reduce swelling, and calms a restless fetus.
Traditionally it is taken as a rich, gelatinous tonic for Kidney and essence depletion with seminal loss, lumbar weakness, dizziness and tinnitus, and to strengthen women during and after pregnancy and steady a threatened fetus. Melted into congee or wine, or dissolved in decoctions, it is also used for bleeding disorders. Being cloying, it is best avoided where Spleen deficiency with poor appetite and dampness predominate.
Relationships
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Botanical Description
Yu Biao (魚鰾), also called Yu Biao Jiao (魚鰾膠) or fish maw, is the dried swim bladder of various large fishes, principally species of croaker (Sciaenidae, e.g., Nibea, Pseudosciaena, Argyrosomus) and sturgeon (Acipenseridae). The bladder is removed, cleaned, flattened, and dried into translucent yellowish sheets composed largely of collagen; processed gelatin (Yu Biao Jiao) is prepared by further boiling and drying. In traditional Chinese medicine, fish maw is classified as sweet and neutral, entering the Kidney channel, and is used to tonify Kidney essence, nourish blood, stop bleeding, and benefit the sinews. Classical indications include seminal emission, infertility, lumbar weakness, hemorrhage, and slow wound healing. As an animal-derived gelatinous product, no plant fields apply.
Active Constituents
Type I collagen
Structural protein (fibrillar collagen)The dried swim bladder of a sciaenid fish is essentially a collagen sheet, and collagen is the component the drug and the food are valued for. Direct characterisation of swim bladder collagen in the genus has been done in the congener Nibea coibor rather than in Nibea albiflora: there, type I collagen and its col1a1 and col1a2 genes dominate the tissue, TGF-beta/Smad signalling drives its deposition, and collagen XII organisation rather than gross composition determines the texture that the market grades. Ingested collagen is digested to peptides and amino acids, so any systemic effect is a nutritional and peptide effect, not delivery of intact collagen to a target tissue.
Glycine, proline and hydroxyproline
Amino acidsThe characteristic amino acid triad of collagen and the residues that dominate the hydrolysate of fish maw. Hydroxyproline is the analytical proxy used to quantify collagen in swim bladder tissue, and dietary proline and hydroxyproline supply promotes collagen deposition in the swim bladder itself in the congener Nibea coibor.
Collagen-derived bioactive peptides
PeptidesPeptides released from swim bladder protein are the most plausible route to any pharmacological effect. Seven novel angiotensin-I-converting-enzyme inhibitory peptides with cytoprotective activity have been isolated and identified from croaker swim bladder byproducts, but that work used the miiuy croaker Miichthys miiuy, a different sciaenid genus, not Nibea albiflora. No equivalent peptide characterisation of Nibea albiflora swim bladder has been published, so this constituent is inferred from a relative and should be treated as such.
⚠ Drug Interactions
Substituted maw from CITES Appendix I Totoaba macdonaldi and other threatened sciaenids including the Critically Endangered Bahaba taipingensis
Dried swim bladder is one of the most heavily mislabelled products in the traditional trade. Mini-DNA barcoding of 350 Chinese-market fish maw samples, of which 347 sequenced successfully, found a mislabelling rate of 51.01%, and the illicitly traded species identified included Totoaba macdonaldi, a Gulf of California sciaenid listed on CITES Appendix I so that all international trade is illegal. Demand shifted to totoaba as the closely related Chinese bahaba, Bahaba taipingensis, collapsed. A separate molecular survey of 503 maw samples from Singapore and Malaysia, priced from 59 to 53,375 US dollars per kg dried, identified further endangered species and recommended new CITES listings, and found a high proportion of identified species to be data-deficient or unassessed. An earlier 16S rRNA survey of croaker maw on sale in Hong Kong reached the same conclusion about conservation risk. Because the drug is dispensed as a dried sheet with no diagnostic morphology, a supplier's species claim is unverifiable at the counter.
Clinical note: Do not dispense fish maw of unknown provenance. Where a patient wants it, use farmed material with documented species and origin, and be aware that high-priced 'premium' maw is more likely, not less, to be a threatened wild species. Record the supplier.
Tetrodotoxin-bearing porcupinefish (Diodon liturosus, Diodon hystrix) maw substituted into the trade
The same mini-DNA barcoding survey of the Chinese fish maw market identified Diodon liturosus and Diodon hystrix among the species substituted into products, and flagged them as a significant health risk because of tetrodotoxin. This is not a taxonomic footnote: it means that a patient given an unverified fish maw may be receiving material from a tetrodotoxin-bearing fish rather than from a sciaenid. The authors call for accurate species identification and stricter labelling on exactly this ground.
Clinical note: Treat unexplained perioral or distal paraesthesia, weakness or dysphagia after fish maw as a possible tetrodotoxin exposure and manage as a poisoning, not as a herb reaction. This alone is reason enough to refuse fish maw of unverified species.
Fish protein allergy and fish-derived excipients or vaccines
This is a fish-derived drug, so it should not be given to a patient with fish allergy. Collagen and gelatin are less allergenic than muscle parvalbumin and fish gelatin is widely tolerated, but the dried bladder is not a purified gelatin, may carry residual muscle and connective tissue protein, and the species is frequently not what the label says, so the allergen actually present cannot be predicted. No case series of allergic reaction to fish maw specifically was located.
Clinical note: Contraindicated in known fish allergy. Also worth declaring to patients who avoid animal products on religious or ethical grounds, since the pinyin name gives no indication that the drug is an animal product.
Historical Texts
Ben Cao Gang Mu
Ming dynasty, 1596References
- Xing B, Chen X, Wu Q, Wang Y, Wang C. Species authentication and conservation challenges in Chinese fish maw market using Mini-DNA barcoding . Food Control (2025) [DOI]
- Seah YG, Wainwright BJ. An Assessment of the Fish Maw Trade in Singapore and Malaysia Reveals Threatened Species and Highlights the Need for a More Complete Assessment of the Conservation Status of the World's Fishes . Conservation Letters (2025) [DOI]
- Tuuli CD, Sadovy de Mitcheson Y, Ng WC. Molecular identification of croaker dried swim bladders (maw) on sale in Hong Kong using 16S rRNA nucleotide sequences and implications for conservation . Fisheries Research (2016) [DOI]
- Wen J, Zeng L, Sun Y, Chen D, Xu Y, Luo P. Authentication and traceability of fish maw products from the market using DNA sequencing . Food Control (2015) [DOI]
- Zhang H, Lin J, Guo H, He X, Jiang W, Yan L, Yan K, Wen X, Lin F. Proteomics-Based Investigation of Sexual Dimorphism in Swim Bladder Texture of Chu’s Croaker (Nibea coibor) . Foods (2025) [DOI]
- Zhu WY, Wang YM, Suo SK, Zheng SL, Wang B. Isolation, identification, molecular docking analysis, and cytoprotection of seven novel angiotensin I-converting enzyme inhibitory peptides from miiuy croaker byproducts-swim bladders . Frontiers in Marine Science (2022) [DOI]
- Chen C, Li A, Liu S. Characterization of the Complete Mitochondrial Genome of Nibea chui: Resolving a Taxonomic Controversy and New Phylogenetic Insights into Sciaenidae . Biology (2026) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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