Leeches are a type of parasitic worm. Leech therapy involves applying leeches to a wound to increase circulation, improve blood flow, and promote healing. Its practice has varied over time, but it continues to be used in modern surgery.

Historically, leeches have been used for various medicinal purposes as far back as 1500 BCE.

Today, they’re mostly used in plastic and reconstructive surgery. This is because leeches secrete peptides and proteins that work to prevent blood clots. These secretions are also known as anticoagulants. This keeps blood flowing to wounds to help them heal.

Medicinal leeches have three jaws with tiny rows of teeth. They pierce a person’s skin with their teeth and insert anticoagulants through their saliva.

The leeches are then allowed to extract blood for up to 45 minutes at a time from the person undergoing treatment. This equates to a relatively small amount of blood, up to 15 milliliters per leech.

There are several situations in which leech therapy may be used. People who may benefit include those who risk limb amputation due to the side effects of diabetes, those who have been diagnosed with heart disease, and those who are undergoing cosmetic surgery in which they risk the loss of some of their soft tissue.

The therapy has also been recommended to treat blood clots and varicose veins.

People with anemia, blood clotting conditions, or compromised arteries are not candidates for leech therapy. Children under the age of 18 years old and people who are pregnant are also usually advised to avoid it.

During a session, live leeches attach themselves to the target area and draw blood. They release the proteins and peptides that thin blood and prevent clotting. This improves circulation and prevents tissue death.

The leeches leave behind small, Y-shaped wounds that usually heal without leaving a scar.

Leeches may be effective at increasing blood circulation and breaking up blood clots, which is why they may be helpful in treating circulatory disorders and cardiovascular disease.

Heart disease

Animal experiments have shown that leech therapy may improve heart disease because of its potential to improve inflammation and blood flow.

A 2021 case study also showed that leech therapy was beneficial for a person with vascular disease.

Cancer

Cancer treatments using leech therapy are being explored because of the platelet inhibitors and special enzymes contained in leech saliva.

While people with certain blood cancers are not advised to use leech therapy, it may slow the growth and spread of lung cancer to other parts of the body.

Similarly, another 2021 study concluded that leech saliva proteins might offer a new way to treat cancer, particularly breast cancer, by targeting the blood vessels that tumors need to grow.

However, further research is needed to develop this into a stable and effective treatment.

The progression of diabetes can cause numerous problems.

These problems can lead to vessel diseases that limit or prevent blood from reaching the legs and feet. When blood flow becomes severely restricted, the affected tissue can die. This is the leading cause of amputation among people with diabetes. Losing a digit or limb due to complications from diabetes is a major concern for millions of people worldwide.

The most effective way to stop this process is to increase circulation to the affected tissues without the risk of blood clots. Research has shown that leech therapy can play a role.

An older case study showed how traditional Unani medicine, which includes leech therapy, was able to help save the foot of a 60-year-old woman with diabetes. Synthetic forms of leech saliva now exist, but researchers have discovered that using as few as four leeches in one session can help reduce the risk of amputation.

Leeches are a Food and Drug Administration (FDA)-approved treatment to help heal transplanted tissue by reducing blood flow problems and improving healing. Leech therapy has been used in reconstructions affecting the following body parts:

  • digits (fingers and toes)
  • lips
  • ears
  • nipples
  • nasal tip
  • penis

Leech therapy’s effect on blood clotting during and after these surgeries helps the body to heal more naturally and completely.

Leech therapy’s benefits for blood circulation has also led some people to use leech therapy to help with hair loss on the scalp in people with folliculitis decalvans. Indeed, a 2022 case study observed this benefit in one person. However, it’s important to note that leech therapy was also combined with Ayurveda medicine.

One risk associated with leech therapy is the risk of bacterial infection, sometimes involving drug-resistant bacteria, so make sure to avoid leeches outside of a regulated environment.

For this reason, people who are immunocompromised by autoimmune disease and environmental factors are not good candidates for leech therapy.

Sometimes blood will ooze out of the area that has been treated and the site of the leech bite will not close. Leeches may also try to move to another area of the body where you do not need treatment, causing unnecessary blood loss.

On occasion, a person will discover during or after leech therapy that they’re allergic to leech saliva.

If complications such as these occur, you’ll know right away and will no longer be a candidate for this treatment method.

Is leech therapy safe?

Leech therapy is typically a very safe procedure. However, there are potential complications such as infection around the wound site, prolonged bleeding, and an allergic reaction to leech saliva.

How painful is leech therapy?

Leeches produce an anesthetic during attachment, so leech therapy is usually painless. If a person experiences pain during leech therapy, they should let their healthcare professional know.

What is the success rate of leech therapy?

According to a 2022 study, the success rate of leech therapy after surgery to reconnect fingers or toes decreases with the duration of treatment:

  • 1 to 3 days: 69%
  • 4 to 7 days: 42%
  • More than 7 days: 8%

However, this data is only applicable to cases where blood flow problems occur after surgeries to reconnect fingers or toes. It does not apply to all uses of leech therapy.

Do hospitals use leeches?

Yes, hospitals in the United States sometimes use leech therapy. Typically, it’s used in relation to plastic and reconstructive surgery.

It makes some people uncomfortable to imagine leeches being used as a modern medical treatment.

Historically, leeches were relied upon for centuries as an essential part of medical care.

In recent times, we’re starting to discover more about the special properties in leech saliva. It may very well be that the treatment has even more practical use than we would have ever thought possible.

That said, it’s important to note that the literature on leech therapy is largely limited to case reports and more rigorous research is needed to fully understand its potential benefits.