Lateral Epicondylitis (Tennis Elbow)

Off-label use with two RCTs showing significant pain reduction at 7-12 weeks compared to topical NSAID and conventional physiotherapy.

Tier B — RCT-supported off-labelStudied off-labelLast updated: 2026-05-26 · Reviewed by ASH Editorial Board

Patient Summary

Is this FDA-cleared for this use?: No — investigated off-label. The FDA cleared medicinal leeches in 2004 only for venous congestion in microsurgical reconstruction (K040187). Use for tennis elbow is supported by published research but not FDA-evaluated.
What evidence exists?: Two small randomized trials (Bäcker 2011, n=49; Stange 2012, n=31) found single-session leech therapy reduced tennis elbow pain compared to NSAID gel at 7 days, with benefit persisting through about 12 weeks. The trials are from a German research group, are small, and long-term outcomes (beyond 6 months) are not well studied. This does not replace standard treatments such as physical therapy, eccentric loading exercises, or, in some cases, steroid injection.
Main risks: Bleeding and oozing from each bite site for several hours, sometimes up to 24 hours
Itching, redness, and irritation at the bite sites for days to weeks
Mild bruising around the elbow
Local skin infection or, rarely, Aeromonas infection from leech gut bacteria
Allergic reaction to leech saliva (uncommon)
Small permanent scars at the bite sites
Who should not consider this: Patients taking blood thinners such as warfarin, apixaban, rivaroxaban, dabigatran, or heparin
Patients with hemophilia or other inherited bleeding disorders
Patients with severe anemia (hemoglobin under 10 g/dL)
Patients with a weakened immune system, especially severe neutropenia
Patients with an active skin infection at the elbow
Patients who had a steroid injection in the elbow within the last 4 weeks
Pregnant patients (relative caution, especially first and third trimester)
What to ask your clinician: Have I tried first-line treatments such as activity modification, eccentric loading exercises, and physical therapy?
How does leech therapy compare with steroid injection, platelet-rich plasma, or surgery for my severity?
What is the realistic chance it will help me, and for how long?
What is the practitioner's training, supplier, and Aeromonas prevention plan?
What is the cost, and is it covered by insurance? (usually not, as off-label)
What is the plan if pain returns — repeat session, injection, or referral?
Are there any restrictions on lifting or gripping after the session, and for how long?
When to seek urgent care: Bleeding from a bite site lasting more than 24 hours
Spreading redness, warmth, pus, or red streaks around the bite sites
Fever above 38.0 C / 100.4 F or chills
Sudden severe elbow pain, swelling, or loss of arm strength
Hives, facial swelling, throat tightness, or breathing difficulty

What this does NOT mean

It does not mean leech therapy is FDA-approved for tennis elbow — it is not.
It does not mean leeches fix the underlying tendon problem — exercise rehabilitation remains the foundation of treatment.
It does not mean leech therapy is better than physical therapy or eccentric loading exercises — those have stronger long-term evidence.
It does not mean every patient improves — individual results vary, and some patients see no benefit.

Safety cross-references

Clinical Profile

Category: musculoskeletal
ICD-10: M77.10, M77.11, M77.12
Safety tier: low

Evidence Summary

A single randomized controlled trial (2011, n=40) compared one session of local leech therapy (2-4 leeches) to a 30-day course of topical diclofenac in chronic lateral epicondylitis of at least one month's duration. At day 7 the pain sum score fell from 143.7 to 95.3 in the leech group versus 131.6 to 134.7 with diclofenac (mean difference -49.0; 95% CI -82.9 to -15.1; P=0.0075); by day 45 the between-group pain difference had narrowed as diclofenac caught up, but functional disability (DASH) still favored the leech group (P=0.0007). Proposed mechanisms combine local anti-inflammatory effects of leech salivary components with analgesic and local decongestant ('bloodletting') effects. Evidence rests on this single small trial; long-term outcomes beyond about six weeks are not well characterized, and use remains investigational.

Treatment specifics

How many leeches, where they are placed, how long a session lasts, and whether to repeat are clinical decisions made by a qualified provider under institutional protocol — not something to self-administer. Discuss the specifics with a clinician experienced in medicinal leech therapy. (Clinicians: switch the audience selector in the top bar to “Clinician” to view protocol detail.)

Key Trials

Bäcker M et al. (2011), n=40 · PMID 21368667 · ASH analysis →
Stange R et al. (2012), n=31

Participants per key trial (n). Larger trials generally carry more statistical weight; case series with unspecified counts are omitted.

Detailed Trial Entries

2 trials indexed in the ASH RCT Library with full Study Profile, GRADE rating, and clinical implications:

Contraindications

Active anticoagulant therapy (warfarin INR >2.0, DOACs, heparin)
Hemophilia or other bleeding disorder
Severe anemia (Hb <10 g/dL)
Active bacteremia or sepsis
Known hypersensitivity to leech salivary proteins
Pregnancy (relative — first/third trimester)
Immunocompromised state with severe neutropenia
Recent local corticosteroid injection (<4 weeks)

Related Conditions

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Off-label use with three RCTs showing pain and function improvement comparable to NSAID gel at 3 months in mild-to-moderate symptomatic knee OA.

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Off-label use with RCT evidence: single-session leech therapy reduces pain and improves function in CMC-1 (basal thumb) OA at 8 weeks.

Plantar Fasciitis

Off-label use with one RCT showing significant heel pain reduction at 6 weeks compared to conservative care.

Fibromyalgia

Investigational adjunctive use; one small pilot suggests transient improvement in tender-point and quality-of-life scores. Not a primary treatment.