Leech Therapy

Patient Experience

  • Reference Number: HEY-1336/2022
  • Departments: Plastic Surgery
  • Last Updated: 31 January 2022


This leaflet provides written information to help you understand the indications, benefits, risks and alternatives to leech therapy. This leaflet should answer most of your questions and is intended to support a clinical discussion between you and your doctor. If you have any additional questions or concerns about treatment, please speak to the doctor or nurse caring for you.

What are Leeches and why is Leech therapy recommended?

Leeches are organisms known for drawing away small quantities of blood from animals for food. A subtype of leeches (‘Hirudo medicinalis’) is specially cultivated for medical use.

In plastic surgery, leeches may be recommended for use in order to improve the blood flow in skin tissue or skin flap that has blood circulation problems. Excess build-up of blood (congestion) and blood clots can be removed by leeches. This reduces the swelling of the tissues and the circulation in small blood vessels is improved. As a result, surgically transferred tissues (flaps) or re-attached fingers which are risk may be prevented from dying.

How does Leech therapy help me? (Benefit)

Leeches attach to the skin tissue or skin flap and release a local anaesthetic which reduces pain at the site of attachment. They also secrete a substance that helps to open up blood vessels (vasodilator) and two other substances (hirudin and calin) that work by thinning the blood (anti-coagulant).

The leech may stay attached to the affected site for between 15 to 60 minutes. After the leech has dropped off, blood drainage from the puncture wound continues for up to 10 hours.

Tissues at risk may be salvaged through the repeated application of leeches. Leech therapy may be recommended when further surgery is not feasible or in order to avoid another operation. Over time, the affected tissue will be able to establish new circulatory channels to keep it healthy without the need for leech therapy.

What are the risks of Leech therapy?


Despite being specially farmed for use on patients, leeches contain bacteria in their gut that allows them to digest blood. There is hence a small risk of transmitted infection from the leeches. Your doctor will give you an antibiotic for the duration of your leech therapy to prevent an infection as this could affect the outcome of your operation. Please tell your medical team if you are allergic to any medicines.


The leech puncture wounds may continue to drain blood for hours after the leech has dropped off. Your healthcare professional will check the wounds regularly for blood loss and your blood count will be monitored to see if you require a blood transfusion.

What are the alternatives to Leech therapy?

Further surgery to improve the blood flow in surgically transferred tissues (flaps) or re-attached fingers that have blood circulation problems may be an alternative to leech therapy. However, this may not be feasible or has already been attempted.  Leech therapy may also be recommended to prevent the need for another operation.

If nothing is done, your blood may clot and prevent adequate blood flow to the tissues or skin flap. This may lead to some or all of the tissue dying and could result in your skin flap or finger being removed at a later stage.

How do I consent for Leech therapy?

When the clinical decision for leech therapy is taken, this treatment is discussed with you by the medical team, including the benefits, risks and the need for antibiotics during treatment. A verbal consent from you is typically taken after the discussion if you are happy to proceed, which confirms that leech therapy can start and that you understand what is involved. This is documented in your clinical notes.

What happens during Leech Therapy?

The nursing team are primarily in charge of monitoring you and the area for treatment during leech therapy. Before the leeches are applied, the area for treatment will be cleaned. Usually, one leech at a time is applied by the nursing or medical team to the skin tissue or skin flap or finger. How many leeches are used and how often the leeches are to be used will be assessed by the medical team.

When the leeches are applied, they are guided to the area to be treated and allowed to attach to the skin tissue or skin flap or finger. The leeches produce an anaesthetic during attachment, so leech therapy is usually painless. Please let your nurse or doctor know if you experience any discomfort during treatment.

The leeches are typically contained at the area for treatment by a small container or dressings. You will be asked to stay in a position such as bed rest or with you hand on a pillow, that will allow leech therapy to take place smoothly without interruption.

Nurses will regularly check for the colour of the skin tissue or skin flap or finger during treatment, as well as the amount of oozing at the area for treatment. Some oozing is expected with leech therapy and doctors will monitor your blood count on a regular basis.

The leeches may stay attached to the affected site for between 15 to 60 minutes. After the leeches have finished feeding, they usually drop off and are removed by the nursing team. Each leech is used only once and is humanely disposed of after removal. Another leech may be re-applied if appropriate.

It may take up to five days and sometimes longer for the circulation to the skin tissue or skin flap or finger being treated to improve, so leeching should not be stopped too soon. Antibiotics that are started for leech therapy are stopped when leech therapy is complete.


This leaflet was produced by the Plastic Surgery Department, Hull University Teaching Hospitals NHS Trust and will be reviewed in 3 years. 

Ref: HEY1336/2022

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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