How to Kill Fleas With 20 Mule Team Borax

Fleas can be more than a nuisance – they can make everyday life miserable, and, if left untreated, they can make you and your pets sick. Not all flea treatments are equal as some are safer than others. If you're looking to get rid of fleas without the use of harsh chemicals, you may have the answer in your laundry room in a box of 20 Mule Team Borax detergent. Using borax for fleas is an all-natural treatment that can rid your home of the pests in a few easy steps.

Adding powdered borax to bottle of water, using spoon, close-up
credit: Russell Sadur/Dorling Kindersley/GettyImages
How to Kill Fleas With 20 Mule Team Borax

What is 20 Mule Team Borax?

As people search for "green" alternatives to harsh chemicals, borax has seen a surge in popularity for use as a natural cleaner and pesticide. Borax is versatile and its use as a rust remover, floor cleaner, liquid plumber, china cleaner and natural herbicide is well known. It's even an ingredient in homemade slime recipes that are endlessly popular with kids. 20 Mule Team Borax is a brand of the borax chemical made in the United States. Established in the late 19th century, the product name 20 Mule Team Borax comes from the 20 mules used to pull 10 tons of borax ore on wagons through the rugged Death Valley terrain after mining.

Borax, also referred to as sodium borate, sodium tetraborate and disodium tetraborate, is a natural mineral with the chemical formula Na2B4O7 • 10H2O. Its primary use is for cleaning, but it has many additional applications, including that of a pesticide. Borax will not only kill fleas, but it will also kill other insects including those that feed on human or animal blood and plant juices. Borax, however, doesn't kill insects in more immature stages of growth.

Borax and boric acid aren't the same thing, despite their similarities. Both are white powders that dissolve quickly in water. Both contain boron, a naturally occurring mineral. However, Borax comes from mines or evaporated deposits. Boric acid comes from borax itself and is hydrated salt that's made by acidifying Borax. You can also use boric acid for fleas.

How a Flea Infestation Occurs

Fleas are small external parasites that live on pet fur or outside in dirt or grass. They travel by hopping from pet to pet or from those outside areas onto your pet. From there, they can make their way into your home via your pet's fur, and once they're inside, it can be difficult to rid yourself of their presence entirely. Fleas reproduce quickly – in a matter of days – and infest themselves in bedding, furniture, rugs and floor cracks. They thrive in warm, moist places, and, while infestations usually occur in the summer months, fleas can live all year round in climates where temperatures never go below freezing.

As parasites, fleas feed off of blood. They generally live from ingesting your pet's blood, but they can also feed off of birds and humans. If you've ever seen small bites around your ankles, it's likely they were caused by fleas. Fleas don't have wings so they can't fly, but they can jump up from your carpet on to you to feed. Stepping on fleas won't necessarily kill them either; they're small enough to burrow in tiny, hidden areas all around your home and have armored shells that protect them from being crushed. If you have a big enough flea infestation, you may actually see them jumping or notice your pets scratching more than usual.

Illnesses Caused by Flea Infestation

If left alone, fleas can not only make your life miserable, but they can cause serious illness to you or your pet. For most people, flea bites appear as small red dots that itch and, if scratched, bleed. The diseases caused by fleas are varied and can be quite serious if not addressed.

  • Allergies: After a flea breaks the skin, the human body reacts to its saliva with "histamines" – chemicals that defend the immune system from the bite. The bite then becomes a red, itchy bump surrounded by a red halo as a result of histamines. This, in turn, causes you to want to scratch the afflicted area. However, if you scratch a flea bite, it will get bigger and the itching will increase.
    When you're allergic to flea bites, your immune system goes into hyperdrive and releases far more histamines than it should. This can result in greater swelling around the bite, hives or a rash and even a severe allergic reaction called anaphylaxis. Anaphylaxis symptoms can include difficulty breathing and swelling in other parts of the body. It can be fatal if not treated immediately. If you believe you have anaphylaxis caused by flea bites, taking Benadryl or an EpiPen injection may help. However, do not hesitate to call 911 if you have a severe allergic reaction.
  • Bubonic plague: Fleas carried by rodents to humans were the cause of the "Black Death," a pandemic that killed approximately 25 million people in the 14th century. Some cases still originate from the Southwestern U.S. every year, albeit on a much smaller scale as a result of the invention of antibiotics.
  • Murine typhus: This flea-borne disease is rare in North America, but some cases still crop up in the Southwestern United States. Like bubonic plague, murine typhus occurs when fleas jump from rats to humans. Symptoms include fever, chills, headache, weakness and nausea. The treatment for murine typhus is also antibiotics.
  • Tungiasis: This flea-borne disease is also rarely seen in the United States, but cases can crop up as the result of international travel to tropical regions where the fleas that carry it are prevalent. The burrowing flea, also known as the jigger or sand flea, carries the virus by locking onto the feet and burrowing into the skin. If you travel to a tropical region, make sure to wear close-toed shoes when walking on sand. If tungiasis goes untreated, it can cause tetanus, gangrene and tissue death. Surgical extraction of the fleas and antibiotics are the usual course of treatment.
  • Tularemia: Also caused by fleas transmitted from rodents to humans, tularemia can be serious if not treated. Symptoms include fever, chills, joint pain, nausea, weakness and diarrhea. While tularemia is not an infectious disease, antibiotics are still the usual course of treatment.

Using 20 Mule Team Borax to Kill Fleas

Using 20 Mule Team Borax to kill fleas in your home is easy and effective. However, make sure to take the necessary safety precautions for you and your pets before starting the process. Keep your pets away from the area when using borax and be sure to wear a mask and gloves. The steps for using borax to kill fleas are as follows:

Step 1: Get a coffee can or a glass jar with a lid and poke holes in the lid with a pencil.

Step 2: Fill your coffee can or glass container three-fourths of the way with 20 Mule Team Borax and add 2 tablespoons of baking soda. Shake well so that the Borax and baking soda mix together.

Step 3: Sprinkle the mixture liberally on your carpet and furniture where the flea infestation exists. You can "scrub" the mix into your carpet a little deeper by using a steel brush.

Step 4: Leave the mixture on the carpet and furniture for as long as possible, and remember to keep pets and family members out of the treated areas during this time.

Step 5: Vacuum the excess mixture thoroughly and throw the vacuum bags in the trash outside to prevent fleas, their larvae and eggs from coming back inside.

Borax works by removing moisture from fleas after they ingest it. They don't consume it willingly as they do blood, but the mixture sticks to their exoskeletons, legs and antennae and fleas "clean" themselves by licking it. In doing so, they ingest the sodium content and dehydrate from the inside out. This method kills fleas in the adult, larvae and pupae stages naturally.

However, flea eggs do survive the process. A week or two after application, you may see fleas all over your home as they'll hatch at once to avoid dehydration. To kill this second and final round of fleas, use a topical flea spray.

20 Mule Team Borax is only useful and safe for use in your environment. It's not safe for use on your pets. Do not put borax on your pet's skin or otherwise treat your pet's fleas with it. Please use a veterinary-recommended medicine to rid your dog or cat of fleas. Also, don't use 20 Mule Team Borax directly on human skin.

Is Borax Safe for People?

While 20 Mule Team Borax isn't toxic in and of itself, that doesn't make it entirely safe for use. Unlike other salt-based chemicals, borax doesn't cause skin irritation. In 2006, the Environmental Protection Agency found no evidence of cell toxicity or toxicity from exposure. However, researchers in parts of the world find borax to be a health risk in that overexposure to it could increase the risk of various cancers and damage fertility.

The National Institutes of Health has also found that borax exposure can cause adverse health effects in humans. While findings between government organizations can be somewhat contradictory regarding borax, keeping children and pregnant women away from it is the best course of action. The adverse effects of borax exposure are as follows:

  • Irritation: Exposure and inhalation can irritate skin and eyes. Some people have reported skin burns or rash, mouth infection, respiratory issues, nausea and vomiting.
  • Hormone disruption: High exposure to borax can reduce sperm count and libido in men and can reduce ovulation and fertility in women. Borax is also said to cause low birth rates and other fetal development issues.
  • Toxicity: Researchers have linked borax exposure to organ damage and poisoning.
  • Death: Fatal doses of borax for adults are from 10 to 25 grams. Ingesting as little as 5 to 10 grams of the substance can kill a young child. For children, exposure can come from slime made from borax or crawling on a borax-treated carpet.

Is Borax Safe for Pets?

Borax is toxic to both your pet's skin and internal organs. It can cause respiratory problems in cats and may cause additional problems if ingested. Borax clings to cat hair and if a cat licks itself, it can cause poisoning if consumed. Symptoms include weakness, seizures, vomiting and diarrhea. Activated charcoal can neutralize the toxic effects of borax in your cat.

If dogs ingest borax, they too can experience vomiting and diarrhea and can also experience stomach pain, drooling, excessive thirst, irritated skin, seizures and respiratory ailments. Chronic ingestion may damage a dog's organs including the endocrine system and brain and can lead to death. Activated charcoal can also neutralize borax toxicity in dogs.

If you believe your pet has become sick from exposure to borax, contact your vet for treatment. If you have any questions about using 20 Mule Team Borax as a pesticide or any other questions about its safety for use in your home, contact the makers of the product at borax.com or call 1-800-872-6729.


Michelle Nati

Michelle Nati

Michelle Nati has written DIY and home improvement articles for The Farmers’ Almanac, ApartmentShowcase.com, and Oddee.com. She holds a B.A. in Communications and English from Niagara University.