Pet Meds for Fleas & Public Health Concerns

This post is one of a series. If this topic interests you please see:
My Cat Has Fleas: Earth Friendly Solutions
My Cat Has Fleas: Update
Pet Meds Don’t Work
Spot-On Pet Medications Might Not Be As Safe As You Think


Too busy to read a wall of text? Here’s the short version:

The best way to control flea populations is to practice good housekeeping. Groom your pet everyday with a pet comb. At least once per week, vacuum the floor and don’t skip the baseboards or areas under the furniture. Wash pet bedding at least once per week. These practices will take care of 96% of the flea population. Skip the pesticides if you can. Pesticide use will eventually create resistant flea populations — if they haven’t already. There is a correlation between poor pet health and the use of flea medications.

But can pet meds harm people?

more after the break

How do the insecticides in pet medications work?

As TexasDeb mentioned in a comment, anti-flea meds are neurotoxins. Neurotoxins adversely affect function in both developing and mature nervous tissue. In simple terms, they cause brain damage.

Typical symptoms of neurotoxin poisoning found in humans include problems with memory, concentration, reaction time, sleep, thinking, language, as well as depression, confusion, personality changes, fatigue and numbness. They can cause allergic responses, seizures, tremors and cardiopulmonary arrest.

Veterinarians and pet groomers do take precautions against exposure but pregnant women and children should also be very wary about contact with these pesticides.

Pyrethrins and Pyrethroid-Affiliated Products

Some of these anti-flea products contain pyrethrins. These poisons attack both the nervous and immune systems and despite what you may read on the internet they are not safe. The most severe poisonings have been reported in infants, who are not able to efficiently break down pyrethrum.

Here’s a story you might not want to read. Trigger warning: heart-breaking death of a child …

Two-and-a-half-year-old Amber Nickol McKeown had head lice. Her mother, Eileen, put the child in a warm bath and massaged Osco Lice Treatment Shampoo into her scalp. Problem solved.

But when Eileen lifted Amber from the tub, she noticed her daughter’s chest had turned red. She called her husband, James, upstairs, and the couple tried bathing Amber in cool water. The little girl’s condition deteriorated quickly. She labored to breathe. Her eyes rolled back in her head, and her skin peeled off in clumps, according to a lawsuit filed by the family.

Amber was rushed from her home in Lester, Pennsylvania, to Fitzgerald Mercy Hospital, where the staff found burns over 60 percent of her body. She was in respiratory distress, and her heart and lungs couldn’t supply her body with oxygen.

On November 4, 2000, within 72 hours of her bath, Amber was dead.

For a long time people thought pyrethrins must be safe because they come from a natural source — a chrysanthemum flower. But a toxin is a toxin whether it comes from a plant or a lab. Pyrethrin and pyrethroid-affiliated products are deadly — to all animal life. These poisons do not select for insects.  The Centre for Public Integrity used freedom of information requests to mine the EPA for their data on these toxins:

Using EPA statistics, the CPI found that human health problems caused by the two insecticides, including deaths, jumped 300% during the decade that ended in 2007. No other class of pesticides has triggered as many adverse reports during the past five years.

Shame on the EPA for not reporting this without a FOIA request.

Organophosphates and Carbamates

Organophosphates and carbamates are also found in anti-flea medications. After the second world war companies like Bayer had huge stockpiles of chemicals. They got creative and developed all kinds of fertilizers, pesticides, herbicides and fungicides. Bayer in particular had some experience with deadly chemicals. After all, they developed the gas used to kill people in the concentration camps.

There is no question that this class of poison is deadly. They not only attack the nervous system but also affect fertility, growth, and development. Alone, they are deadly but they are usually accompanied by so-called ‘inert’ ingredients that boost their toxicity and are sometimes not even specified.

Autism, PDD and other Concerns

Studies such as this one and others are surfacing, though not widely reported, linking the use of these pesticides with autism and other developmental disorders. Exposure risk seems to be greatest during the second trimester of pregnancy.

SuperFleas and Human Disease

My neighbourhood made the news and even drew the attention of the CDC a couple of years ago. Apparently, some of my neighbours had been sickened by murine typhus. TYPHUS!? Like, is this the middle ages or something? There are two diseases called typhus and the one that put my neighbour into the hospital was the one carried by fleas. Everyone blamed the opossums but I think they were fellow victims as much as a source of disease.

Half our homes have pets. Our pets carry fleas outside. Wild animals get infected. The two populations of wild and domesticated animals swap fleas back and forth with domesticated animals extending the flea season by creating a refugia for fleas indoors. I worry that if we do breed superfleas resulting in a population boom people will use the fact as a justification for using even more toxic chemicals … not to mention the potential for creating a vector for epidemics.

When it comes to using these chemicals I have decided the risks dwarf any advantages.


6 thoughts on “Pet Meds for Fleas & Public Health Concerns

  1. My husband and I run a large pet care business, and work with many veterinarians. Against all advice given, and all public opinion, we have quietly refrained from using flea and tick control on our pets. I have seen many pets with complications from flea applications, but also many pets who suffer from lyme disease… it is a difficult choice, but we don’t want to put pesticides on or near living things! We try to contain our pets away from tick infested areas, check them regularly, and keep chickens (they love to eat ticks)


    1. Chickens! That is a brilliant solution. I am so glad to hear people like you and your husband are out there making difficult choices but doing what is best for everyone’s health. Thank you.


  2. Whenever a choice is made to use a chemical to poison a life form precautions are called for. Chemicals are indiscriminate. A nervous system is a nervous system.

    In the lack of evidence of what (if any) a safe level of exposure might be to any particular chemical poison, a careful evaluation of the risks from the pest vs. the risk from the poison must be made. No toxin that goes on to (or even in to) your pet ONLY goes on to or in to your pet. Chemicals are best used rarely, only as a last resort, and under strict guidelines.


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