Have you heard you can use borax for fleas? We found this natural method very helpful in eliminating our flea problem. Not many people have heard of using borax to kill fleas, so it felt like we were using a secret weapon.
It is a white powder, commonly used as a household cleaner. I discovered 20 Mule Team Borax when my children were young and I bought some at the local grocery store to use as a laundry booster.
I would just add some in with the laundry detergent and it seemed to help everything come out brighter and fresher.
When we got fleas, I was surprised to learn that this same product in my laundry room could be used effectively as a natural treatment for getting rid of them!
It's important not to confuse borax powder, also called sodium borate, with boric acid. They both contain the same chemical element, boron.
Many people use these words interchangeably, but they are different.
Borax, or sodium borate, is a combination of boron, sodium, and oxygen.
Borax is found and extracted from natural locations like dry river beds. Borax powder is used as a common household cleaner and laundry additive.
Boric acid is also a fine white powder but is commonly used in pest control. Boric acid is borax that has been processed and refined. It is composed of hydrogen, boron and oxygen.
According to The Chemical Company, boric acid may be prepared by reacting borax (sodium tetraborate decahydrate) with a mineral acid, such as hydrochloric acid. Boric acid is used as a pesticide and is considered poisonous. 
Both boric acid in it's powder form and borax powder contain boron. Boric acid, as a pesticide and insecticide, works by being ingested and poisoning the stomach and damaging the nervous system.
Borax is a desiccant, which means it dries out, or dehydrates insects. Both can cause issues if ingested or inhaled, so we'll review how to use borax for fleas safely further down.
According to medlineplus.gov, boric acid is a dangerous poison.  Since 20 Mule Team Borax is readily available and has low toxicity, we'll talk about using borax for fleas.
When you have fleas, it seems like they are everywhere in the house. And they pretty much are. Adult fleas like to lay their eggs on pets, and the eggs fall off pet's fur when they walk around.
Then as the eggs become larvae, they will wriggle, wiggle and burrow toward dark corners and crevices, to pupate and emerge as adults. So the use of borax to kill fleas in the house should be restricted to these areas:
Areas to Target:
Wearing gloves and a face mask, gently sprinkle the powder in these areas. In hard places use a broom or stiff brush to sweep the borax powder into the cracks and crevices.
In the upholstered or carpeted areas, use a broom or bristle brush to work it into the fabric or fibers.
Leave sprinkled borax for 6 to 48 hours, ensuring no pets or children come in contact with it during that time. Some people do this overnight.
Then vacuum the area as thoroughly as possible. Use a hose attachment to get into those cracks.
Vacuuming stimulates flea pupae to hatch and it kills fleas, so it's essential to dispose of the vacuum bag or vacuum canister contents outside of the house immediately.
Borax is a desiccant, which means it may kill flea larvae, flea eggs and adult fleas by absorbing moisture and drying out, or dehydrating them.
It does not kill them on contact, but works slowly so it requires patience and repeated treatments.
Since fleas are not known to groom themselves, and since the borax needs to be ingested, it may only be somewhat effective at best – and likely only with the larvae that are scavenging and feeding on flea excrement and therefore may consume some of the borax.
“How do I know if I have pure borax?”
20 Mule Team Borax is pure borax, just how it's found in nature. There are natural flea products on the market that are composed of a mixture of ingredients. The popular Fleabusters comes to mind.
If this interests you, buying a premixed flea killing powder with safety instructions and precautions is always a wise choice.
"Is Borax Safe For Dogs?"
Borax can be used in homes with dogs as long as they don't come in contact with it.
Never use it directly on your dog, or on their pet bedding or any areas where they can walk or lay on it.
Keep them away from the treated areas until thoroughly vacuumed.
"Is Borax Safe For Cats?"
Cats can get into smaller places and are prone to washing themselves, so in addition to making sure never to use it on them or their bedding, take special precaution that they can't track it on their paws or come into any contact with it. If they do, call your vet immediately.
"Is Borax Safe Around Small Children?"
For the safety reasons above, it's not recommended for use in households with kids. It shouldn't come in contact with young children or even pets.
If you have kids and pets in the house, consider a safer powder like food-grade diatomaceous earth which is used in exactly the same manner but with no toxic or harmful effects.
"How Well Does Borax Kill Fleas?"
Giving your home the borax treatment is definitely useful, especially when you don't have pets or children but do have fleas in the house.
It works slowly – so you may notice fewer fleas over time. It's effectiveness depends on vacuuming and using other methods like regular pet baths at the same time.
"Does Borax Kill Fleas In All Stages of the Flea Life Cycle?"
While it may do a good job of killing flea larvae by drying them out, flea eggs and adult fleas won't ingest it so it's effectiveness is questionable.
There are conflicting reports from pet owners who have used borax for fleas. Additionally, flea pupae are virtually indestructible, locked in their tank-like cocoon.
Vacuuming them will be your best bet, but having borax or other powder such as table salt or diametreous earth in place when they hatch will help kill them too.
"Is Using Borax For Fleas all I need to do?"
Fighting flea infestations takes quite a bit of work! Simply using a flea powder or borax for fleas won't be enough.
For best results you will also want to be giving your pet flea baths with either a good flea shampoo or just dawn dish soap, as well as daily use of a flea comb both in and out of the bath.
Also, vacuuming daily is critical, as well as frequent washing and heat drying of pet bedding, human bedding, blankets, throw rugs, decorative pillows and pillow covers etc.
If you can and want to treat your pet with a topical flea treatment, that will quickly make a big difference. Other products such as flea collars, flea spray (store-bought or homemade), and even flea traps are important for fighting flea infestations.
If we had another flea infestation, I wouldn't.
Now that I know about food-grade diametreous earth (DE) and now that there are great natural flea powders on the market like Fleabusters - made by professionals, for the purpose of killing fleas, properly pre-mixed, and come with instructions, I would choose one of those natural options.
Even though we felt that we had success using borax for fleas, it could have been largely due to the stepped-up vacuuming efforts in those areas where we had placed it.
Also, it most likely only affected the larvae. In the future, I'd choose a safer, more effective option.
Borax - The Chemical Company. (n.d.). The Chemical Company. Retrieved February 16, 2022, from https://thechemco.com/chemical/borax/#:~:text=Borax%20occurs%20naturally%20in%20evaporated,repeated%20evaporation%20of%20seasonal%20lakes.&text=Tibet%20and%20Romania.-,Borax%20can%20also%20be%20produced%20synthetically%20from%20other%20boron%20compounds,decahydrate%2C%20is%20not%20acutely%20toxic.
Boric acid poisoning: MedlinePlus Medical Encyclopedia. (n.d.). MedlinePlus. Retrieved February 16, 2022, from https://medlineplus.gov/ency/article/002485.htm#:~:text=Boric%20acid%20is%20a%20dangerous,products%20that%20contain%20the%20chemical.
Borax (Sodium Tetraborate): Uses & Health Risks. (n.d.). WebMD. Retrieved February 16, 2022, from https://www.webmd.com/a-to-z-guides/borax-sodium-tetraborate#:~:text=The%20best%2Dknown%20use%20for,Paint%20and%20ceramic%20glaze