# What would happen if I used a dose of my cat's flea medicine on myself? **URL:** \ **Category:** Factual Questions\ **Created:** [August 4, 2014, 4:28pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796 "2014-08-04T16:28:35Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Smapti](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smapti/32/17938_2.png) [@Smapti](https://boards.straightdope.com/u/Smapti)\ **Post date:** [August 4, 2014, 4:28pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/1 "2014-08-04T16:28:35Z")
So my cat’s got the fleas again, and I gave him a dose of Frontline Plus on the back of the neck yesterday morning. So far, it’s working like a charm - I haven’t seen a single live flea on him since last night. Of course, there are still countless eggs and larvae and other baddies lurking in the nooks and crannies of my house, and since jumping on the cat is a no-go, the remainder of them have decided to go after the only other uncontaminated food source in the house - i.e., me. And it’s driving me crazy, but aside from picking them off of my skin and crushing them when I see them, there’s not much I can do about it. “Or is there?”, I thought as the title of this thread crossed my mind. Allow me to be clear; I am not seeking actual medical advice, and I do not actually intend to use Frontline on myself. I’m just pondering what would actually happen if I were to take a dose of Frontline (or Advantage or a comparable medicine) and use it on myself the same way one uses it on a pet, by applying it to the skin at the base of the neck. My gut tells me that it’d most likely do little to nothing due to the weight difference between me and the animal it’s intended for, but suppose we scaled the dosage up to a size where it would be proportionate to my weight? Would it kill any fleas that tried to bite me? Would it kill _me_ because of some toxic side effect? Would it have toxic effects on other organisms I came in contact with, or spread through my clothes or through food or other objects I handled? Would it just do nothing except make me smell real bad? (I mean, there must be a good reason it wouldn’t work, or else the pharmaceutical companies would be making bank off selling the ultimate insect repellant.) Again, speaking purely in the hypothetical here as I have absolutely no intention of experimenting on myself. Just chalk it up to fighting ignorance. ---
**Author:** ![Bert\_Nobbins](https://avatars.discourse-cdn.com/v4/letter/b/aeb1de/32.png) [@Bert\_Nobbins](https://boards.straightdope.com/u/Bert_Nobbins)\ **Post date:** [August 4, 2014, 5:06pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/2 "2014-08-04T17:06:48Z")
I spilt some Frontline on my fingers once when struggling with a reluctant cat. I noticed no effects at all, no headache, nothing. Body weight is certainly going to be important. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [August 4, 2014, 5:12pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/3 "2014-08-04T17:12:18Z")
It is the same chemical as is in roach poison. ---
**Author:** ![anson2995](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@anson2995](https://boards.straightdope.com/u/anson2995)\ **Post date:** [August 5, 2014, 1:04am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/4 "2014-08-05T01:04:20Z")
The active ingredient is fipronil, which is an insecticide. It can be a skin irritant, and definitely should not be ingested. It’s not going to kill you, but it’s not likely to do anything about the issue, either. Fleas rarely take residence on human hosts, they just like to bite you. People do not need to be treated for fleas. Treat the cat, treat the environment, and you’ll stop itching in a few days, ---
**Author:** ![Fishtar](https://avatars.discourse-cdn.com/v4/letter/f/ed655f/32.png) [@Fishtar](https://boards.straightdope.com/u/Fishtar)\ **Post date:** [August 5, 2014, 2:26am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/5 "2014-08-05T02:26:01Z")
It would fully work (you would need the large dog size though). Every flea who bit you would die. Neither Imidaclopridand or fipronil are much toxic to mammals in such dosages . But you would sill get bit… Get some insect repellant? Fleas do not like DEET. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [August 5, 2014, 2:40am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/6 "2014-08-05T02:40:43Z")
> [@anson2995](#): > > The active ingredient is fipronil I remember reading up on this. I seem to remember that this is a tobacco extract. I want to say it’s approved for crops, but that part is a bit fuzzy. It’s illegal for a vet to say it’s been know to work on human head lice in the United States … the laws and results in Europe may be different. ---
**Author:** ![Sunny\_Daze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunny_daze/32/438_2.png) [@Sunny\_Daze](https://boards.straightdope.com/u/Sunny_Daze)\ **Post date:** [August 5, 2014, 6:14am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/7 "2014-08-05T06:14:29Z")
I did a little checking. Short answer. It’s a neurotoxin and possibly a carcinogen (although I imagine you’re not planning on making a habit of using it). A better choice would be the DEET already recommended. Also, visit a pet store, or ask your vet, and get a flea bomb for the house, since it sounds like you’ve got quite an infestation going. If you don’t want to go the “bomb” route, vacuum the house, wash your bedding, use the DEET, and it should get better fairly quickly. There may be a “bloom” as eggs hatch in about a week, so you’ll have to repeat the vacuuming. If we’re talking 5-10 of the little bastards, vacuum, etc. If we’re talking unknown hordes, bomb, bomb, bomb… I hate fleas _shivers_ ---
**Author:** ![Crazier\_Catlady](https://avatars.discourse-cdn.com/v4/letter/c/b9e5f3/32.png) [@Crazier\_Catlady](https://boards.straightdope.com/u/Crazier_Catlady)\ **Post date:** [August 5, 2014, 6:28am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/8 "2014-08-05T06:28:35Z")
I’ve been wondering the same thing, only I use Stronghold on my cats (active ingredient selamectin), which also kills off worms and mites. I get the stuff on my fingers regularly when I apply it to my cats. Will it relieve me of worms, too? Is it in any way dangerous? ---
**Author:** ![Donnerwetter](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Post date:** [August 5, 2014, 11:31am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/9 "2014-08-05T11:31:21Z")
To expand on this: are there drugs/medications that are benifcial for animals but ineffective or dangerous if taken by humans? ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [August 5, 2014, 11:40am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/10 "2014-08-05T11:40:09Z")
Aspirin is helpful to dogs and humans … but poisonous to cats. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [August 5, 2014, 12:02pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/11 "2014-08-05T12:02:13Z")
> [@watchwolf49](#): > > Aspirin is helpful to dogs and humans … but poisonous to cats. I believe you are thinking of acetaminophen. Aspirin is used in cats, although the dosing frequency is extreme (every 72 hours, IIRC). ETA: [Cite](http://pets.webmd.com/cats/guide/safe-cat-pain-medications). > [@](#): > > A baby aspirin given every three days is a typical safe cat dose. It should only be given with food and not on an empty stomach. At the first signs of toxicity, the drug should be withdrawn. > [@](#): > > Acetaminophen (Tylenol) is another analgesic that must never be given to cats. A cat given even a child’s dose of Tylenol can develop fatal hemolytic anemia and liver failure. ---
**Author:** ![Carlarm](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@Carlarm](https://boards.straightdope.com/u/Carlarm)\ **Post date:** [August 5, 2014, 10:00pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/12 "2014-08-05T22:00:56Z")
If you have carpet in your house I strongly recommend Fleabusters powder. It is non-toxic to everything but fleas. You work it into your carpet and it lasts until the next time you shampoo the carpet. It takes a couple weeks to have its effect. I’m a little surprised the company is still around because it is a flea control product you only have to buy once. You’ll probably end up not having to use Frontline again. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [August 5, 2014, 11:59pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/13 "2014-08-05T23:59:54Z")
> [@Carlarm](#): > > If you have carpet in your house I strongly recommend Fleabusters powder. Fleabusters powder is just horrendously overpriced boric acid. You can buy the same product at about 1/2 the price at any good garden shop. > [@](#): > > It is non-toxic to everything but fleas. NO!!! It definitely is not non-toxic. Boric acid has an LD50 of about 10g/kg. That is marginally \*more \*toxic than the most common pyrethroid insecticides. It is in no sense non-toxic. > [@](#): > > You work it into your carpet and it lasts until the next time you shampoo the carpet. Which is true of any residual insecticide you choose to apply. > [@](#): > > It takes a couple weeks to have its effect. No. Like all residual insecticides, it doesn’t work until the dormant fleas hatch from their cocoons. That can be a few weeks or a few years. Boric acid isn’t a slow acting toxin. If it worked at all, it wouldn’t take weeks. > [@](#): > > I’m a little surprised the company is still around… The company is in business because it is selling boric acid at [$13 a pound](http://www.fleabuster.com/Products/Rx_Plus/flea_powder.html) when you can buy the stuff from a garden shop or lab supplier for [$5 a pound](http://www.rosemill.com/category_s/33.htm) retail. > [@](#): > > … because it is a flea control product you only have to buy once. No, you have to buy it just as much as any other product. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [August 6, 2014, 12:11am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/14 "2014-08-06T00:11:22Z")
What about diatomaceous earth instead of Fleabusters™? ---
**Author:** ![SeaDragonTattoo](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@SeaDragonTattoo](https://boards.straightdope.com/u/SeaDragonTattoo)\ **Post date:** [August 6, 2014, 12:19am UTC](https://boards.straightdope.com/t/what-would-happen-if-i-used-a-dose-of-my-cats-flea-medicine-on-myself/694796/15 "2014-08-06T00:19:56Z")
Wash everything you can get into the washer and dryer. Vacuum everything else. Sprinkle diatomaceous earth around. The topical flea medications for cats and dogs work by binding with the lipid layer of the skin and fur follicles. That layer is not the same in people and the medication won’t work because it won’t spread nor will it stay on. Putting it on yourself just won’t do anything at all except maybe give you a rash if you’re sensitive to it.