Living therapy · Drug-discovery frontier
The medicinal leech: a living therapy and a drug-discovery frontier.
The medicinal leech is two things at once. It is a living clinical therapy — FDA-cleared for venous congestion in reconstructive microsurgery, with a growing evidence base across other conditions. And it is a drug-discovery frontier: the 440+ proteins of its secretome seeded FDA-approved anticoagulants (desirudin and bivalirudin in clinical use; lepirudin since withdrawn) and remain mostly uncharted. The American Society of Hirudotherapy curates 141 years of evidence for both, verifies every citation, and opens the field to clinicians, researchers, and partners.
Peer-reviewed research · Independent 501(c)(3) · 1,400+ publications · 71 authoritative sources · 30 documented safety events
141
Years of leech-derived science
From Haycraft 1884 → Markwardt 1957 → Bivalirudin 2000
440+
Characterized salivary proteins
Babenko et al. 2020 · expanded 2025
78%
Microsurgical flap salvage rate
Whitaker et al. 2012 · n=277 systematic review
Structured registries — live counts
Conditions, compounds, trials, biographies, jurisdictions. Auto-updated at render time as ASH expands its knowledge base.
199
Conditions
FDA-cleared, off-label & investigational — Tier A/B/C
201
Compounds
Salivary pharmacology: hirudin, eglins, destabilase, more
169
RCTs
GRADE-rated trials, PMIDs verified against PubMed
68
Biographies
Investigators across antiquity through modern molecular biology
155
Jurisdictions
Global regulatory survey — honest 'unregulated' markers
10,030
Research articles
PMID-verified library — target 10,000 (long-term roadmap)
100% of 10,000
Where would you like to start?
Three pathways into evidence-based hirudotherapy
FOR PATIENTS & FAMILIES
Find evidence-based answers
Sixty-three patient questions with evidence-graded answers. Locate qualified practitioners. Understand what to expect.
Patient Guide →
FOR CLINICIANS & RESEARCHERS
Access the evidence base
1,400+ indexed peer-reviewed publications. Safety protocols. Implementation playbooks. Open research questions.
Clinical Evidence →
SUPPORT THE WORK
Support open medical knowledge
Recognized 501(c)(3) nonprofit. Every gift supports peer-reviewed evidence generation, clinician education, and patient access.
Make a Gift →
Discoveries from the field
Three questions our research community is working to answer
BIOCHEMISTRY
Why does leech saliva contain 440+ distinct proteins?
Liu et al. (2019) catalogued the medicinal leech secretome at unprecedented depth. Most of those 440+ proteins remain functionally uncharacterized — each a potential next-generation anticoagulant, antimicrobial, or anti-inflammatory drug lead.
Read the science →
CLINICAL EVIDENCE
Six RCTs · Cohen's d = 0.82 · what does this mean for knee OA?
Three decades of randomized controlled trials (Michalsen 2003, Andereya 2008, Stange 2012, and more) show pain reduction effect size larger than topical NSAIDs and comparable to intra-articular corticosteroid — for an off-label indication patients ask about every week.
Explore the evidence →
FRONTIER MEDICINE
Frontier biology: fibrinolytic mechanisms under preclinical investigation
Bobrovsky, Baskova et al. (2021) demonstrated in-vitro dissolution of aged, organized human clots by recombinant leech destabilase — a preclinical observation with potential implications for thrombosis biology in stroke, pulmonary embolism, and chronic thromboembolic disease. Translation to clinical efficacy has not been established.
See breakthrough horizons →
HOW WE EVALUATE EVIDENCE
GRADE framework · ASH evidence tiers · open research questions.
We distinguish FDA-cleared indications from off-label applications on every page. We acknowledge what we don't yet know — 42 open research questions catalogued. We are a 501(c)(3) nonprofit with a public conflict-of-interest policy and a transparent correction log.
Read our editorial methodology →What we do
Safe institutional adoption
A ten-phase Implementation Playbook covering stakeholder alignment, clinical protocols, pharmacy workflow, nursing training, infection prevention, quality metrics, billing, and regulatory compliance — synthesizing best practice from leading microsurgical centers.
Read the playbook →Practitioner training & education
A five-level educational framework from medical-student survey through reconstructive-microsurgery fellowship and continuing medical education. Competencies, learning objectives, assessment methods, faculty resources.
See the curriculum →Research leadership
1,400+ indexed publications. 71 authoritative external sources mapped. 42 open research questions identified. 30 milestones across 141 years documented. 12 breakthrough horizons mapped.
Open the research library →U.S. medicinal leech supply
A public-benefit infrastructure project focused on biosecurity, chain-of-custody documentation, antimicrobial resistance surveillance, and domestic-source resilience for the world's third-most-prescribed living medical device.
Read the proposal →Latest research
Open the full library →Novel Leech Antimicrobial Peptides — Hirunipins
Kumar et al. (2025) — Advanced Science (Wiley)
Cysteine-rich AMPs with broad-spectrum activity and antibiotic synergy
Read analysis →
Leech Therapy for Knee Osteoarthritis — The Landmark RCT
Michalsen et al. (2003) — Annals of Internal Medicine
First RCT showing leech therapy superior to topical diclofenac for OA pain
Read analysis →
Leech-Assisted Flap Salvage — Systematic Review of 277 Cases
Whitaker et al. (2012) — Microsurgery
Evidence base for the FDA-cleared microsurgical indication
Read analysis →
“Where 141 years of evidence meets the next decade of breakthrough medicine.”
Questions?
Get in touch with the Society
Whether you are a patient, clinician, researcher, partner, or member of the press, we would be glad to hear from you.
Engage with the Society
Six additional pathways for participants in our mission
Healthcare professionals
Clinical protocols, evidence summaries, safety guidelines, and pharmacology data for physicians, nurses, and allied health.
Access clinical resources →
Patients & caregivers
Sixty-three evidence-graded answers to common questions. Understand expectations, safety, off-label vs. cleared indications.
Open the patient guide →
Researchers & academics
1,400+ indexed publications. GRADE methodology. Open research questions catalogue. Collaboration opportunities.
Research library →
Become part of the Society
Donors & sustaining members
Tax-deductible contributions advance peer-reviewed research, clinician training, and patient education. 501(c)(3) since 2023.
Make a tax-deductible gift →
Professional members
Join clinicians, researchers, and educators advancing evidence-based hirudotherapy. Quarterly journal access, member directory, CME pipeline.
Join the Society →
Regulators & policy makers
Comprehensive 510(k) history, CDRH→CBER jurisdictional crosswalk, international regulatory comparison, transparent correction log.
Regulatory documentation →
Press, partners & media
Press kit with organizational facts, expert spokesperson availability, approved quotes, photography, and partnership inquiries.
Open press kit →
FDA-cleared indications are explicit on every clinical page. Investigational and off-label uses are clearly labeled. Read our editorial methodology for our evidence-grading framework.