Medicinal Leech Species Guide
Detailed comparison of H. medicinalis, H. verbana, and H. orientalis
Last Updated: March 5, 2026Reviewed by: Andrei Dokukin, MD
Last updated: March 14, 2026
While the term “medicinal leech” is often used generically, there are distinct species with different morphological characteristics, geographic distributions, and salivary profiles. Understanding these differences is critical for clinical standardization and FDA compliance.
Hirudo medicinalis — European Medicinal Leech
- Distribution: Western and Central Europe (native range now severely reduced)
- Conservation status: CITES Appendix II (protected species due to historical over-collection)
- Morphology: Dark green to olive-brown dorsal surface with prominent lateral stripes (longitudinal red-brown bands)
- Size: Up to 20 cm when fully extended
- Clinical significance: Historical “gold standard” for medicinal use, but now rare in commercial supply due to conservation restrictions
- Salivary profile: Well-characterized hirudin (HV1 isoform), reference standard for pharmaceutical research
Hirudo verbana — Hungarian Medicinal Leech
- Distribution: Eastern Europe, Mediterranean region, Black Sea basin
- Conservation status: Not CITES-listed (more abundant than H. medicinalis)
- Morphology: Olive-green to brown with mottled dorsal pattern (less distinct striping than H. medicinalis)
- Size: Similar to H. medicinalis (15-20 cm)
- Clinical significance: Most commonly used species in modern clinical practice. Often historically mislabeled as H. medicinalis.
- Salivary profile: Hirudin HV2 isoform (slight sequence variation from HV1, similar potency)
- FDA status: Primary species from FDA-cleared U.S. suppliers (e.g., Biopharm)
Hirudo orientalis — Oriental Medicinal Leech
- Distribution: Middle East, Caucasus, Central Asia
- Conservation status: Not CITES-listed
- Morphology: Variable coloration (green to brown), often with spotted or reticulated pattern
- Size: Slightly smaller than H. medicinalis (10-15 cm)
- Clinical significance: Used in traditional medicine in Russia, Turkey, Iran. Increasingly studied in modern research.
- Salivary profile: Hirudin HV3 isoform (distinct pharmacokinetic profile)
- FDA status: Not currently FDA-cleared for U.S. clinical use
Hirudo troctina — North African Medicinal Leech
- Distribution: North Africa (Morocco, Algeria, Tunisia)
- Conservation status: Not CITES-listed
- Morphology: Similar to H. verbana with regional variations
- Clinical significance: Limited clinical data; not widely used
- FDA status: Not FDA-cleared
Comparative Table
| Species | Size | Range | Dorsal Pattern | Hirudin Isoform | FDA Status | Availability |
|---|---|---|---|---|---|---|
| H. medicinalis | 15-20 cm | Western Europe | Dark green, lateral stripes | HV1 | Historically cleared | Rare (CITES protected) |
| H. verbana | 15-20 cm | E. Europe, Mediterranean | Olive-green, mottled | HV2 | Cleared (primary) | Common |
| H. orientalis | 10-15 cm | Middle East, Caucasus | Spotted/reticulated | HV3 | Not cleared | Regional use only |
| H. troctina | 12-18 cm | North Africa | Similar to <em>H. verbana</em> | HV-like | Not cleared | Limited |
Species Mislabeling
Most leeches sold as H. medicinalis in the United States are actually H. verbana — a taxonomic correction that has significant implications for clinical standardization and research reproducibility.
Educational Disclaimer
This page describes biological properties of medicinal leeches for educational purposes. Discussion of biological mechanisms does not constitute evidence of therapeutic efficacy.