American Society of Hirudotherapy

Diverse molecular data demonstrate that commercially available medicinal leeches are not Hirudo medicinalis

Research article published in Proceedings. Biological sciences (2007)

Last Updated: November 1, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsSalivary PharmacologySiddall M et al. · Proceedings. Biological sciences, 2007

Abstract

The European medicinal leech is one of vanishingly few animal species with direct application in modern medicine. In addition to the therapeutic potential held by many protease inhibitors purified from leech saliva, and notwithstanding the historical association with quackery, Hirudo medicinalis has been approved by the United States Food and Drug Administration as a prescription medical device. Accurate annotation of bioactive compounds relies on precise species determination. Interpretations of developmental and neurophysiological characteristics also presuppose uniformity within a model species used in laboratory settings. Here, we show, with mitochondrial sequences and nuclear microsatellites, that there are at least three species of European medicinal leech, and that leeches marketed as H. medicinalis are actually Hirudo verbana. Beyond the obvious need for reconsideration of decades of biomedical research on this widely used model organism, these findings impact regulatory statutes and raise concerns for the conservation status of European medicinal leeches.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeComparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.
Indexed MeSH termsAllelesAnalysis of VarianceAnimalsBase SequenceCommerceDNA PrimersDNA, MitochondrialEuropeLeechesMicrosatellite RepeatsModels, GeneticMolecular Sequence DataPhylogenySequence Analysis, DNASpecies Specificity

Summary

Mitochondrial sequences and nuclear microsatellites showed that at least three European medicinal leech species exist and that leeches marketed as Hirudo medicinalis are actually Hirudo verbana, with implications for biomedical research, regulation and conservation.

Why This Matters for Hirudotherapy

This study used mitochondrial DNA sequences and nuclear microsatellites to examine the species identity of commercially available European medicinal leeches, demonstrating that leeches marketed as Hirudo medicinalis are actually Hirudo verbana and that at least three distinct European medicinal leech species exist. H. medicinalis is noted as FDA-approved as a medical device, while the species in commercial circulation may differ. The work is strictly molecular and taxonomic in scope, providing no clinical outcome or therapeutic efficacy data.

Citation

Reference (Vancouver style)

Siddall ME, Trontelj P, Utevsky SY, Nkamany M, Macdonald KS. Diverse molecular data demonstrate that commercially available medicinal leeches are not Hirudo medicinalis. Proc Biol Sci. 2007;274(1617):1481-1487. doi:10.1098/rspb.2007.0248. PMID: 17426015

Bibliographic details (authors, volume, pages, DOI) are taken from the PubMed record.

Added to ASH library: March 18, 2026 · Site last updated: November 1, 2026

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.