How to Kill Leeches

Co-authored by Elmer Bensinger

Last Updated: July 16, 2024 References

Leeches are typically water-dwelling invertebrates related to worms. They will feed by attaching themselves to a host and sucking its blood. If a leech attaches itself to your body, it can seem gross and be uncomfortable. However, if you follow the right steps for safely removing the leech, there is very little danger or cause for concern. If leeches are a persistent problem in your area, you can also take steps to control their population.

Method 1

Method 1 of 2:

Removing Leeches from Your Body

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1
Try to detach the leech’s suckers. Locate the leech’s oral sucker on the anterior (thinner end). Place your finger or fingernail on the skin next to this, and gently slide it underneath. Push to the side to detach the leech. Repeat this step at the posterior end sucker, then flick the leech off of your body.
- Push the leech away as you detach it, because it will try to reattach itself to your body.
- Make sure to start with the thinner, anterior end, which is actually the leech’s “head.”^{[1]
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- Dispose of the leech away from the water after you have detached it. You can pour salt on the leech to ensure it is killed, but do this only after you have safely removed it.
2
Wait for the leech to fall off. Once the leech has had enough blood, it should fall off on its own, typically after about twenty minutes.^{[2]
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Research source} If you cannot remove the leech safely, you may have to leave it and wait until it stops feeding. While this can be unsettling, the leech should not cause you any pain or serious injury.
- Dispose of the leech after it falls off. You can pour salt on the leech to ensure it is killed, but do this only after it detaches itself from your body.
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Leeches have anticoagulant enzymes that cause blood to flow freely.^{[3]
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Research source} If the bite area continues to bleed after you remove the leech (or after it falls off), apply gentle pressure with a clean cloth or gauze until the bleeding stops.
Leeches can leave a small wound where they were attached to your body.^{[4]
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Research source} Clean this wound using warm water and a mild soap. Afterwards, apply an over-the-counter antibacterial cream and bandage. In the event that the wound becomes infected, see a doctor.
Leeches are very flexible and difficult to grasp, and even if you are successful at grabbing one and pulling it off your body, this may make things worse. In ripping it away, parts of the leech’s jaws may remain in your body, which can cause an infection.
Many traditional remedies for removing leeches involve putting a match or flame to the leech’s body, or pouring salt, alcohol, vinegar, or other things on the leech. While this will likely cause the leech to detach itself from your body, it may regurgitate the contents of its stomach back into the bite wound as it detaches. This can cause an infection.^{[5]
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See a doctor if necessary. If leeches are attached to sensitive areas, such as on your eye, or in an orifice such as your nasal cavity, vagina, or penis, you should see a doctor for professional help. Doctors are trained in the use of special techniques and equipment to remove leeches, and will be able to treat any infections or complications that arise.^{[6]
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- You should also see a doctor if, after removing a leech on your own, you notice signs of infection, irritation, or other unusual symptoms.
- Signs of infection can include redness, swelling, or pus at the site of the wound, as well as general pain and fever.

Method 2

Method 2 of 2:

Removing Leeches from Water

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1
Set a trap. Take a metal can with a reclosable lid, such as a large coffee can, and punch small holes in this lid.^{[7]
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Research source} Put raw meat inside the can, close the lid, and tie a string around the can. Place this in shallow parts of water where you suspect leeches live, and they will be attracted to and enter the can. You can then pull the can out of the water and dispose of the leeches.
- Leeches are most active during warm months. Lay your trap, check it daily during warm periods, and dispose of any caught leeches. Repeat this until few or no leeches appear in the trap.^{[8]
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- The exact size of the holes you should punch in the can lid will depend on the species of leech. If no leeches are being caught in your trap, try a larger or smaller hole size until it works.
2
Attract ducks to the leech-infested area.^{[9]
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Research source} Ducks may feed on leeches, which can help to keep their populations low. If you attract ducks using duck feed, however, this can increase levels of phosphorus in water and contribute to algae growth. Species of duck known to consume leeches include:
- Ring-necked duck (Aythya collars)^{[10]
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  The Cornell Lab of Ornithology
  Research lab of Cornell University dedicated to interpreting and conserving the Earth's biological diversity through research and education about birds
  
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- Wood duck (Aix sponsa)
- Muscovy duck (Cairina moschata)
These fish are natural predators of leeches and will help to control their population.^{[11]
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Research source} This method will only work for enclosed, private waters like ponds.
4
Control aquatic vegetation and debris. An overabundance of vegetation and organic debris in ponds and lakes is thought to contribute to the growth of leech populations. If possible, keep vegetation to about ten percent of a pond’s surface area.^{[12]
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Research source} Remove or control any excess vegetation to help combat leech infestation. Methods include:
- Minimizing the feeding of fish and ducks. Their waste provides nutrients that increase the growth of aquatic vegetation.
- Manually removing vegetation from the water. It is best to remove the whole plant, roots and all. Make sure to discard the plants out of the water so that the debris does not nourish future plant growth.
- Dredging or deepening the body of water. The greater depth will make it harder for plants to root.
- Lowering the water level. Shallower water during cold and freezing times will make it more difficult for plants to establish.
- Lining the bottom of the body of water. Plastic sheeting or mineral layers at the bottom of the water can discourage aquatic vegetation.
- Introducing herbivores. A wide variety of ducks, geese, turtles, insects, snails, crayfish, and fish will eat aquatic vegetation and therefore reduce its growth. The Chinese grass carp (Ctenopharyngodon idella) is thought to be a particularly good choice for this method.
- Using aquatic herbicides. Common choices include: Chelated Copper Compounds, Fluridone (Sonar), 2,4-D, Glyphosate (Rodeo, Pondmaster), Diquat, and Endothall (Aquathol, Hydrothol). These may have a range of side effects, including fish kills. They may also need to be applied over and over again, because the vegetation that is killed decomposes in the water and contributes to future vegetation growth.
- Carefully follow all directions provided with herbicides, and contact your local county extension agent before introducing any species that may be considered invasive.
5
Use chemical control methods. Copper sulfate pentahydrate is used to control leech populations. The recommended dose is 5 ppm.^{[13]
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Research source} This approach, however, will kill everything in the water, including fish and other creatures. Thus, this method should be used only in enclosed, fish-less waters.
- Copper sulfate pentahydrate is toxic and must be handled properly. Follow all safety and usage guidelines provided with the product.^{[14]
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How to kill the leech inside my nose?

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If the leech is inside your nose, go to the doctor immediately. Leeches disconnect when they are full of blood, but if they are in a confined space, they may crawl farther up instead of out. If the leech is not inside the nose entirely, don't try to remove it yourself. You won't get a clear angle. Don't leave the leech to fall off unattended.

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What does salt do to the leech?

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Salt absorbs water from them, since their skin allows water passage freely. Salt kills them by dehydration.

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How fast does salt kill leeches?

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Slowly, like any poison. The leech dies slowly within a few minutes.

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There are between 700 and 1000 species of leeches worldwide.^{[15]
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US National Park Service
Agency responsible for the maintenance and promotion of national parks and monuments

Go to source} Most live in water, though some live on land.

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Leeches, though they can cause discomfort, are not known to pass diseases to humans.^{[16]
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Research source} In fact, they were traditionally used medicinally. Occasionally, leeches and leech byproducts are still used medicinally.

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You can prevent leeches from attaching to your body by covering up exposed areas of skin when you are in waters that you suspect may be infested with leeches.

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