American Society of Hirudotherapy

Study on the effect of medicinal leech therapy (Hirudo medicinalis) on full-thickness excisional wound healing in the animal model

Basic science / preclinical published in Research in veterinary science (2022)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportClinical TrialsGenomics & ProteomicsZakian A et al. · Research in veterinary science, 2022

Abstract

The possible impacts of alternative and conventional medicines on wound healing are now of growing interest. This study aimed to evaluate and elucidate the wound healing activity of medicinal leech therapy in wound excision of the rat model. After a round, full-thickness excision was made in the dorsal region of the body, the animals (n = 30) were randomly divided into three equal groups: I) the treatment group (MLT), where the wounds received leech treatment; II) the positive control group (PC), where the wounds received 1% sodium phenytoin treatment; and III) the negative control group (NC), where the wounds did not receive any treatment. On days 6 and 16, wound biopsy specimens were taken, and prepared sections were stained using various methods. The contraction rate differed significantly (P < 0.05) between the NC group and the other groups. The histopathological evaluation revealed that MLT group showed an accelerated healing process and lower inflammatory response compared to other groups. In ML-treated group maturation and remodeling of collagen had occurred, while in 1% sodium phenytoin treated group, proliferation was the prominent feature. Results showed that the fibroblast was significantly lower in the NC group in comparison to other groups. The number of MNC, s, and PMN, s was significantly higher in the NC group compared to other groups (P < 0.0001). In our study, medicinal leech therapy had a higher success rate in healing for the treatment of excisional wounds in animal models.

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

Publication typeJournal Article

Summary

The possible impacts of alternative and conventional medicines on wound healing are now of growing interest. This study aimed to evaluate and elucidate the wound healing activity of medicinal leech therapy in wound excision of the rat model.

Why This Matters for Hirudotherapy

This animal study made full-thickness excisional wounds in rats (n=30) randomly divided into leech therapy, a positive control (1% sodium phenytoin), or no treatment, and reported a significantly different contraction rate between the untreated group and the others, with histopathology showing accelerated healing, a lower inflammatory response, and greater collagen maturation/remodeling and higher fibroblast counts in the leech-treated group. For the secretome drug-discovery story this is mechanistically useful because it ties leech application to measurable tissue-level wound-healing changes (reduced inflammation, collagen remodeling) under controlled conditions, supporting the hypothesis that leech-derived bioactives modulate the healing cascade. The essential caveat is that this is a preclinical rodent model, not a clinical trial; positive results in rat excisional wounds do not establish efficacy or safety for wound care in humans and serve only to motivate further translational work.

Citation

Study on the effect of medicinal leech therapy (Hirudo medicinalis) on full-thickness excisional wound healing in the animal model.

Zakian A et al. · Research in veterinary science, 2022

Added to ASH library: March 18, 2026 · Site last updated: June 18, 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.