American Society of Hirudotherapy
Medicinal Leech Therapy: Patient Handout
Bring this page to your appointment or save it as a PDF.
Medicinal leech therapy is FDA-cleared for venous congestion in surgical grafts, flaps, and replants. It is delivered by a licensed clinician in a clinical setting. Read this handout before your appointment and ask your clinician any questions it raises.
Not for home use
Medicinal leech therapy must be administered by a trained, licensed clinician under sterile conditions with monitoring. Self-application carries serious risks including uncontrolled bleeding, infection (particularly Aeromonas hydrophila), and improper attachment. Do not attempt at home.
Contraindications
Tell your clinician if any of the following apply to you. Some conditions absolutely rule out treatment; others require caution and additional monitoring.
Absolute (do not treat)
- Hemophilia or other significant bleeding disorder
- Active anticoagulation that cannot be safely paused
- Severe anemia (Hb < 8 g/dL)
- Known allergy to leech proteins or hirudin
- Severe peripheral arterial disease at the treatment site
- Active local or systemic infection
- Pregnancy (first and third trimester)
Relative (caution required)
- Immunocompromised state (cancer, HIV, transplant, biologics)
- Diabetes mellitus with peripheral neuropathy
- Concurrent NSAIDs or aspirin
- Phobia of leeches or significant anxiety
- Recent dental, surgical, or invasive procedure
- Chronic skin conditions at the proposed site
Before your session
- Eat a light meal 1–2 hours before; avoid alcohol for 24 hours.
- Do not take aspirin or NSAIDs in the 48 hours prior unless your physician has approved it.
- Bring a list of all medications, supplements, and allergies.
- Arrange transportation home in case you feel light-headed afterward.
- Wear loose clothing that exposes the treatment area.
During treatment
- Initial bite is brief; most patients report a pain score of 1–2 out of 10 (a small pinch). Sensation is significantly reduced after attachment.
- Each leech feeds for 30–60 minutes and detaches on its own. Do not pull a leech off.
- Slight oozing of blood is expected for several hours after detachment — this is therapeutic, not a complication.
- Tell your clinician immediately if you feel faint, nauseated, or light-headed.
After treatment
- Keep the treated area clean and dry for 24 hours.
- Take prophylactic antibiotic exactly as prescribed (typically a fluoroquinolone) to prevent Aeromonas infection.
- Apply a clean dressing if oozing continues; change as instructed.
- Avoid heavy lifting, hot baths, and alcohol for 24 hours.
- Plan for someone to drive you home if you feel light-headed.
Seek medical help
Most after-effects are mild. Contact your clinician or seek emergency care if you experience any of the following:
- Bleeding that soaks through dressings, does not slow with 10–15 minutes of firm pressure, or pulses or spurts (arterial pattern)
- Lightheadedness, fainting, severe dizziness, or shortness of breath
- Spreading redness, warmth, or pus at the treatment site
- Fever above 100.4°F (38°C) or chills
- Severe pain at the site or radiating from it
- Signs of allergic reaction (hives, swelling, difficulty breathing)
Emergency: call 911 or your local emergency number immediately.