Leech therapy (hirudotherapy) factsheet


Medical grade leeches are sometimes used in surgery that involved re-attaching a body part, such as a finger and grafting soft tissues, like muscles. This is called hirudotherapy.

In some instances, veins can be damaged after surgery which affects the blood supply. Blood can get into the body part but cannot get out. The old blood stays in the re-attached body part, which means that new blood is unable to supply the area with oxygen and nutrients needed for healing. This is called venous congestion and is identified by swelling and purple dis-colouration of the re-attached body part. If this happens, the re-attached part will often die.

Leech saliva has many substances that stop blood from clotting and helps to improve blood flow. These substances are called anti-coagulants. This makes leech saliva an excellent therapy for treatment of venous congestion.

Medical grade leeches are a species called “Hirudo medicinalis” and are grown specifically for this treatment.

Preparing for the treatment

The medical team involved will help you and provide you with the relevant information on how to prepare your child for the treatment.

 During the treatment

Generally, during hirudotherapy:

  1. a medical grade leech will be placed on the specific body part that has venous congestion
  2. the leech makes a small bite in the body part, injecting its saliva to stop the blood from clotting
  3. the leech consumes a small amount of blood and drops off by itself after about 30-40 minutes
  4. the body part is then left to bleed to allow the old blood to leave the body through the leech bite.

Once the old blood has been bled out, new blood can circulate through the body part.

Sometimes leeches do not want to attach to a body part. This can be because there are chemicals in the skin that the leeches do not like. The nurses and doctors will try to help the leech attach during the treatment.

 After the treatment

The medical team involved will help you and provide you with the relevant information on after treatment care specific for your child.

After the treatment has finished, the leech will contain human blood and cannot be used again as they are contaminated. The leeches are put to sleep humanely after treatment.


Risks of hirudotherapy

Some risks of hirudotherapy include:

  • infection caused by digestive bacteria in the leeches entering the body part – antibiotics are given as part of the treatment to kill this bacteria
  • allergic reaction to leech saliva
  • blood transfusion needed if blood levels drop too low.

Sometimes, even after the treatment, the re-attached body part or graft may not survive.

Common concerns

The biggest problem people have with the treatment is that leeches are not nice to look at.  A disposable cup or covering can be placed over the leech so your child cannot see it.

Leech therapy should not hurt. The re-attached part usually has no feeling, and the leech saliva has substances that prevent pain. If your child experiences pain during or after treatment, let their doctor or nurse know as soon as possible.

Last updated Saturday 27th January 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024