Do Leeches Help with Health Problems?

Leeches offer many health benefits in tandem with other medically supervised treatments. They can prevent blood clots and promote circulation.

Sep 11, 2023By Colt Dodd
do leeches help with health problems

When people think of getting medical treatment for an illness or injury, they may imagine getting blood through a transfusion––not having blood sucked out by a worm-like creature. Yet, contrary to popular belief, leeches actually have many health benefits, helping those with cancer, blood clotting disorders, and diabetes.

As discussed later, leeches have chemicals in their saliva that reduce inflammation and swelling. They can also help with blood circulation. Here, the bloodsucking leech gets a redemption arc as we explain the health benefits it offers.

Leeches Have Health Benefits

old cartoon wtih a leech as a doctor
Image Credit: Wikimedia Commons

On December 14, 1799, George Washington passed away at 67 years old. The reason? He had developed quinsy, an abscess between the tonsils and the walls of the throat. The solution? Attaching leeches to his body. This caused him to lose 40 percent of his blood, ultimately resulting in his death.

Despite this story, leeches do have health benefits. Medical science has come a long way since the days of the Founding Fathers, and doctors may use leeches in conjunction with other treatment methods. While the theory of bloodletting has long been debunked, leeches can assist with blood circulation, pain, and the removal of deadly toxins.

How Do Leeches Even Drink Blood?

leech sucking on someone_s skin
Image Credit: Wikimedia Commons

Leeches suck blood from their prey and thrive off the nutrients. They need blood to grow and reproduce, and both male and female leeches partake in this process. Unlike other bloodsuckers, leeches don’t have jaws or a proboscis. Instead, they attach to the flesh using teeth-like suckers, then suck until blood comes out. A leech can drink five to 10 milliliters of blood in one sitting––about 10 times its body weight.

Believe it or not, leeches usually don’t hurt people. These slug-like organisms use anticoagulants to prevent clotting, and one usually feels a pinch when a leech attaches itself. This can make some difficult to find. Some species of leeches also inject a substance that reduces pain––making it easier to feed and remain undetected.

Leech Therapy Can Help Blood Circulation

a wet leech on a tree
Image Credit: Wikimedia Commons

Healthline notes that the practice of using leeches to promote blood circulation dates back to ancient Egypt. It’s a tried-and-true method that’s proven itself useful over centuries. But how does it work?

Leeches have three rows of sucker-like teeth, and their saliva contains many anticoagulants found in prescription medications. While feeding, they inject proteins and peptides that make blood thin and prevent clotting.

What Does Leech Therapy Entail?

Here’s leech therapy in practice. Imagine that someone comes into the hospital, and they struggle with frequent blood clots. A professional may recommend leech therapy, which would involve:

  • Targeting areas where the patient may develop a blood clot (such as in the arms or legs)
  • Selecting a leech and attaching it to the area
  • Allowing the leech to feed for 20 to 45 minutes
  • Removing the leech after it has removed about 15 milliliters of blood

In the modern age, no one has to worry about having leeches suck out 40 percent of their blood like George Washington. Under the purview of a medical professional, one could experience better circulation and fewer worries about blood clots.

Leech Therapy Helps Patients with Heart Disease

the mark a leech leaves on someone_s skin
Image Credit: Wikimedia Commons

The Indian Journal of Pharmaceutical Sciences notes that leech therapy is a promising treatment for those suffering from heart disease. That’s because, similarly to the treatment outlined above:

  • Leeches thin blood, which is easier for the heart to pump. This also decreases the likelihood of clotting.
  • It’s non-invasive. Many patients with heart disease can’t tolerate certain treatments and medications. Leech therapy usually presents few side effects, and any bite marks heal within a few days.
  • Leeches prevent inflammation. The proteins and peptides in a leech’s saliva minimize tissue swelling and pain. This has prompted doctors to use these worm-like organisms for other vascular disorders.

Leeches Combat Cancer Cells

three leeches on someone_s skin

The Journal of Clinical & Diagnostic Research is exploring how leeches could help cancer patients, particularly those living with lung cancer. Healthline notes that leeches contain platelet inhibitors that prevent pulmonary embolisms. Scientists have also injected leech saliva into mice, finding that it prevents cancer cells from forming and metastasizing.

Could Leeches Benefit Patients with Diabetes? (Yes)

a diagram on how leech therapy works
Image Credit: Wikimedia Commons

Diabetes can cause many problems, with poor circulation being among them. Over time, poor circulation can lead to tissue death, sometimes resulting in foot amputation. Healthline notes that the most effective way to treat diabetes is to prevent blood clots and promote circulation. Enter leeches.

As noted, leech saliva prevents blood from clotting. A recent case study in India suggested that regularly using a leech’s saliva was able to save a 60-year-old woman’s foot from amputation. While this field of study is still emerging, sources note that even a single leech therapy session could benefit a patient’s life.

Can Leeches Actually Cause Health Problems?

a bunch of leeches on a guy
Image Credit: Wikimedia Commons

If someone wants to experiment with leech therapy, they shouldn’t go outside, find a leech on the sidewalk, and stick it on. That’s because leeches can transmit disease. The ones that are used for leech therapy are kept in sterile environments where they don’t develop and transmit illnesses.

Per Healthline, these ailments can include:

  • Malaria. Research shows that leeches can contract malaria from humans, then continue its spread. “Leech Bite” suggests that anywhere from two to 20 percent of leeches used for therapy could have this virus.
  • Hepatitis B. Hepatitis B is an infection of the liver that can result in dark urine, yellowing of the eyes, and stomach pain. It’s preventable with a vaccine.
  • In theory, HIV. Technically, it’s possible for a leech to spread HIV. For this to happen, a leech would have to feed on a host with the virus, then transmit HIV to an uninfected host. However, very few (if any) cases have been reported worldwide.

If it’s any consolation, humans can cause health problems, too. And, just like humans, leeches can prevent life-threatening illnesses.

Colt Dodd
By Colt Dodd

Colt Dodd is a sighthound enthusiast with three years of freelance writing experience. He has an Italian greyhound/Shetland sheepdog mix named Homer. In his spare time, he enjoys going to dog parks and writing fiction.