American Society of Hirudotherapy

Leech therapy for symptomatic treatment of knee osteoarthritis: results and implications of a pilot study

Research article published in Alternative therapies in health and medicine (2002)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Clinical trialClinical TrialsMichalsen A et al. · Alternative therapies in health and medicine, 2002

Abstract

CONTEXT: Leech therapy was a mainstay in conventional treatment for pain from antiquity until the mid-19th century. Its use is still widespread in traditional healing procedures in Asia, Africa, and Arabic countries. There is renewed interest in leech therapy in the field of complementary medicine and empirical evidence for specific benefit in knee osteoarthritis. OBJECTIVES: To determine the effect of leech therapy as an adjunctive treatment in painful knee osteoarthritis, to investigate the onset of action, to evaluate patients' acceptance of this treatment, and to investigate the side effects of the procedure. DESIGN: Observational, controlled, nonrandomized pilot-study. SETTING: Subjects were inpatients of an academic teaching hospital of the University of Essen, Department of Internal and Integrative Medicine, Essen, Germany. PATIENTS: 16 inpatients (mean age 69 +/- 9 years) with a confirmed diagnosis of osteoarthritis of the knee joint; 10 patients were treated with leeches and 6 served as controls. INTERVENTION: A single trial of 4 leeches (Hirudo medicinalis) applied topically at painful periarticular sites of the knee joint in the experimental group (n = 10). Both groups received conventional treatment for pain with the exclusion of nonsteroidal anti-inflammatory drugs. MAIN OUTCOME MEASURES: Self-reported general knee pain, assessed by visual analog scale for 10 days daily and in a follow-up after 28 days. Frequency of adverse effects also was recorded. RESULTS: Periarticular application of 4 leeches led to rapid relief of pain with sustained improvement after 4 weeks in the absence of major complications. CONCLUSION: Leech therapy may be an effective treatment for rapid reduction of pain associated with osteoarthritis of the knee. Its efficacy should be tested in larger randomized controlled trials with assessment of expectation bias.

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

Publication typeClinical TrialControlled Clinical TrialJournal ArticleResearch Support, Non-U.S. Gov't
Indexed MeSH termsAgedAnimalsAnti-Inflammatory Agents, Non-SteroidalFemaleHumansLeechesLeechingMaleMiddle AgedOsteoarthritis, KneePainPain Management

Summary

Leech therapy for symptomatic treatment of knee osteoarthritis: results and implications of a pilot study.

Why This Matters for Hirudotherapy

This observational, controlled, nonrandomized pilot study investigated the efficacy of a single application of four *Hirudo medicinalis* leeches on 10 inpatients with painful knee osteoarthritis, compared to 6 conventional treatment controls. The researchers found that periarticular leech therapy provided rapid pain relief that was sustained over a four-week follow-up period without major complications. These results are directly relevant to the American Society of Hirudotherapy by providing preliminary empirical evidence supporting the clinical use of medicinal leeches for managing localized joint pain. However, the scope is strictly limited by a very small sample size and the lack of randomization, which means the observed pain relief could be heavily influenced by expectation bias and requires validation in larger controlled trials.

Citation

Leech therapy for symptomatic treatment of knee osteoarthritis: results and implications of a pilot study

Michalsen A et al. · Alternative therapies in health and medicine, 2002

Added to ASH library: May 27, 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.