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Does Lysol Kill Fleas on Cats? Effectiveness & Safety Explored

Vet approved

	Dr. Maja Platisa Photo

Reviewed & Fact-Checked By

Dr. Maja Platisa

DVM MRCVS (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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Irritating and extremely difficult and frustrating to eradicate, fleas endanger our pets and homes beyond the bites and unpleasant stigma attached to infestations. Fleas are also hosts to other parasites such as tapeworms, which can hatch inside your cat’s intestine if ingested. In some cats, flea bites will also cause an allergy and lead to severe skin irritation that requires veterinary attention.

Lysol is a popular brand of disinfectants and cleaners. This cleaner, depending on specific formulation, also often contains various amounts of hydrogen peroxide, ethanol and benzalkonium chloride as the main active ingredients. Anecdotally, it may kill fleas, but there is no scientific evidence to prove its effectiveness at all. The chemicals in Lysol and other commercial cleaners are toxic to cats and should never be used on any animals.

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Why Lysol Should Be Avoided Around Cats

Lysol isn’t safe for cats because of several main active ingredients: benzalkonium chloride, ethanol, and hydrogen peroxide.

  • Hydrogen peroxide kills a wide range of bacteria, viruses, yeasts, and spores, while alcohol compounds have a variable effect against bacteria and viruses, depending on specific formulation.
  • Hydrogen peroxide can cause severe tissue damage to your cat’s esophagus and stomach and lead to intestinal bleeding if swallowed. It can also damage the skin.
  • Ethanol and other alcohol preparations used in Lysol are also toxic for your cat, leading to gastrointestinal, respiratory, nervous system, and heart disturbances. Liver and kidneys may also be affected, and alcohol poisoning can lead to death in pets depending on the ingested dose.
  • Benzalkonium chloride is also poisonous for your cat. Signs of toxicity include drooling, fever, and tongue and mouth ulcers. Thus, you’ll always want to keep your cleaning cabinets locked if you have a curious cat. If you suspect that your cat might have licked the surface you cleaned with Lysol or come in contact with it another way, contact your vet immediately.
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Do I Have a Flea Problem?

In case you’re wondering if you have an infestation already on your hands, flea eggs are very small and hard to spot. They are only about 0.5 millimeters in length and have an oval shape. Flea larvae are 2-5 millimeters in length and resemble tiny worms. You are unlikely to see them during an infestation because they quickly burrow deep into carpets, cracks, pet beds, and grass. Adult fleas are easily spotted with the naked eye but may be hard to catch due to their amazing jumping skills.

If you see black, crumbly specks that look like coffee grounds on your cat’s body, you can be sure that fleas are present. These black specks are actually flea poop. They contain dried blood from the host and will turn reddish brown if exposed to water.

Why Fleas Are a Big Deal

A single female adult flea lays on average 20 eggs per day, but sometimes even as many as 50 eggs. Flea eggs make up around half the entire flea population in the home. It only takes 1 to 10 days for the eggs to hatch, depending on temperature and humidity. From there, the larvae quickly grow up over 5-20 days and then form a cocoon (pupa stage). Pupa can survive for months in the environment, but adult fleas will eventually emerge, usually after several days or weeks, when they sense vibrations and movement, rising carbon dioxide levels, or body heat indicating the presence of a host they can feed on. Female fleas will first feed and then start to produce eggs within a few days, and the entire cycle repeats. Since fleas grow and multiply so fast, only a couple of these pesky critters can start an entire infestation.

Cats often suffer from allergies and can be allergic to flea saliva. As little as one flea bite in an allergic cat will cause significant and painful skin irritation and often sores from excessive scratching and licking. These will require veterinary attention.

Fleas serve as intermediate hosts to tapeworms, which means that the tapeworm cannot complete its life cycle without the presence of fleas. If your cat or dog accidentally eats a flea while grooming themselves, these worms can hatch in their intestines. In rare cases, tapeworms may even infest humans, especially children, if they swallow fleas. If you suspect that your cat has fleas, it’s best to speak to your vet about the most appropriate vet-approved flea treatment available so you can get the infestation under control quickly!

tick on cat's skin
Image Credit: thka, Shutterstock

How to Prevent Fleas

Many people believe that fleas are only an issue in the warmer months and are absent in the winter, but this is not actually the case. Temperatures as low as 55.4°F (13°C) will cause a failure in the larvae to pupate, while at 46.4°F (8°C), 100% of pupae will die within 20 days and 72% of pre-emerged adults will die by day 40. Exposure to 37.4°F (3°C) for 10 days and 30.2°F (-1°C) for 5 days is lethal to pre-emerged adults, while the vast majority of pupae will die within a day.

As you can see, colder temperatures drastically reduce flea survival. But even in the winter, your home never gets this cold, so the temperature inside is actually more than adequate for the flea life cycle to continue. This is why you should keep up with preventative flea treatment for your cat even during winter months. Your vet will advise you on the best prescription product available.

Unfortunately, despite your best efforts, you may still occasionally spot a few fleas or some flea dirt on your cat or around your home. The most important prevention and treatments for your cat are based on veterinary-approved medicines that need to be administered appropriately and regularly. This way, you will stop fleas from laying eggs and contaminating your home, causing the vicious cycle to repeat. Alongside this, you should develop a house-cleaning regimen. Just a couple of hours a few times a week cleaning the house can help to prevent infestations, which otherwise can take hours of labor every day and might not resolve for several months. On top of that are the health hazards that come with flea presence, such as tapeworm risk and skin irritation to your cat.

1. Vacuum Frequently

If you can’t wash something, vacuum it well and often. During an infestation, vacuum once daily. Carpet, bedding, and sofas all need to be cleaned and vacuumed at least once a week to clear any possible flea eggs. Be sure to knock out the filter directly into the outside trash can to prevent the tiny flea eggs from landing inside your home.

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2. Spray Fabrics With Natural Flea Repellent

You might consider spraying bedding with a natural product or essential oil-based flea repellent for added protection. A licensed commercial pest control applicator should be contacted for advice on the best products for use in your home and in the yard, especially in shady areas and places where pets spend most of their time. If you are considering natural or even commercial products for indoor use, be very careful not to apply or spray around your cat because many essential oils and ingredients can be toxic. Make sure this product or spray doesn’t contain permethrin, as this chemical is extremely dangerous for cats.

It’s best to speak to your vet before choosing a product for your home. Your local pet store and vet clinic likely sell repellents that are safe to use inside the house and around pets. The treated area needs to dry completely before it’s safe for animals and children to re-enter. You should never use these products directly on your cat, even if some are marketed for use on pets, as there is no evidence to confirm they are actually effective against fleas and no guarantee they are safe for your cat.

spraying on cat
Image credit: Vaillery, Shutterstock
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3. Wash Bedding in Hot Water at Least Once a Week

Machine-wash sheets on the hot water setting every week, especially if your cat sleeps in your bed. You’ll also need to wash their bedding weekly or vacuum it if it’s spot-clean only.

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4. Apply Vet-Approved Flea Prevention Formulated for Cats

The mainstay of flea prevention and treatment for cats is topical and oral medication, many of which require a veterinary prescription. Make sure you treat all the cats in the house, and if you have other pets, they need safe and species-appropriate treatment as well.

If you do have a canine under your roof, take extra care not to mix up their medicine. Pyrethrins and permethrins are common insecticide agents in flea prevention products for dogs, but both are deadly for cats and fish. Products will differ in formulation and the way they affect adult fleas and their developmental stages. Speak to your vet first about the best flea product for your cat, and make sure you discuss any other pets in the house so they are safe for all animals involved.

vet holding magnifying glass searching cat fleas
Image credit: lev.studio, Shutterstock
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5. Put a Halt to Existing Infestations with a Capstar Tablet.

If your cat already has fleas, you might want to give them a Capstar tablet. This medicine starts working within 30 minutes, and all fleas on your cat should drop dead within 48 hours. Capstar tablets are safe for use in cats and kittens as long as they are at least four weeks old and weigh at least two pounds. The product does not require a veterinary prescription. However, speak to your vet if you are unsure how much to give your cat. Capstar will only kill adult fleas and has no effect on larvae, pupae, or eggs. Therefore, your cat and home will still be infested with fleas, as this product is not sufficient for controlling the issue on its own and needs to be combined with other treatment options. Side effects of this medicine are uncommon, but possible.

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6. Flea Comb Your Cat Regularly

Every time you spot the “coffee grounds,” you’ll want to flea comb your cat to make sure fleas don’t get out of hand. But you can also do this on a more regular basis, as it’s a good way to spot flea dirt and fleas. Simply dip the flea comb in a mixture of dish soap and water that will then catch the fleas and stop them from jumping away. Although fleas can survive in plain water for days, the dish soap serves as a surfactant, which causes them to sink and drown. During the hotter times of the year, you may want to flea comb your cat at least once a week to make sure they’re clear. Make sure you are treating your cat for fleas regularly with a safe, vet-approved product.

flea combing a tabby cat, looking for fleas
Image Credit: Simone Hogan, Shutterstock
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7. Consider Keeping Your Cat Indoors or Providing a Secure “Catio” For Outdoor Exercise

One way to minimize your cat’s exposure to fleas could be to keep your cat indoors or control their outdoor activity by providing a safe enclosed space for them to exercise and enjoy the outdoors, such as a “catio.” Of course, fleas will be present in the environment and can reach your cat from other animals that might pass through your yard, such as rodents, but this risk will be lesser in comparison to cats that are exploring the great outdoors regularly. Your “catio” will still need regular cleaning to ensure that there are no flea eggs waiting to hatch. Even indoor cats can get fleas, and this is why regular flea prevention and treatment with a vet-approved product is crucial.

Disclaimer: Please be aware, as we have already mentioned, that some dog flea products on the market are based on compounds called Pyrethrins, which are highly toxic to cats and fish. Please take special precautions, use only cat-specific anti-flea products on your cat according to your veterinarian’s advice, and follow the manufacturer’s instructions carefully. The recommended site, dosage, and frequency of application should never be exceeded. If you have a multiple-cat household, it is recommended to keep your cats separate to avoid ingestion of toxic chemicals via allogrooming. Always consult with your veterinarian before applying any treatment to your cat. Never use a pyrethrin-based product in the same room you keep a fish tank. Use gloves and keep away from children. Kindly dispose of the bottles considering safety precautions. The information about these products has been fact-checked by one of our licensed veterinarians, but the purpose of this post is not to diagnose illness or prescribe treatment. The views and opinions expressed are not necessarily those of the veterinarian. We recommend contacting your pet’s veterinarian before purchasing any over-the-counter flea product.

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Lysol isn’t a safe or effective treatment for fleas. The hydrogen peroxide, alcohol, and benzalkonium chloride chemicals are all toxic to your cat. Plus, there’s no real evidence that Lysol is an effective insecticide. A diligent cleaning routine combined with regular flea control using vet-approved products is the best method to tackle the fleas and keep your cat safe. Speak to your vet about flea prevention and treatment before the infestation gets worse, as you might be feeling the consequences for months.

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