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February 17, 2007


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What type of shampoo can I use on small dog using frontline? She is itching constantly!!! Can I simply bathe w/water and dishsoap, something that doesn't have flea chemicals?


Hello, Robin,

Dishwashing soap will probably be very drying to the skin. Dog and cat skin has a lot different pH balance and is much thinner and more delicate than human skin. We occasionally use Dawn for de-greasing animals that have become contaminated with motor oil or machinery grease, but I wouldn't use it for routine bathing.

I would recommend a soap-free hypoallergenic pet shampoo, like HyLyt EFA. Your veterinarian should be able to help you with this.

Thanks for reading and writing.


Hi, love your site, have been reading through the archives after finding you via a Google search.

We just started our two (inside-only) cats on Advantage, as in they received the first dose this morning. Should we be okay with this? We put it on the base of their skull where they can't reach it (though it didn't stop them from trying!), so they can't lick it off. And like I said, they never go outside and we do not bathe them. Should the Advantage last all month?

Thanks for any info you can provide. Once again, love your site!


Hello, Sarah,

I think you will be happy with the Advantage on your house-cats. It is a good product, but it can't stand much bathing. Since most house-cats don't get much bathing, this should be no problem.

For my patients that go in and out, I really like Revolution because it also gives me heartworm prevention and protection from ear mites (which require direct contact to catch, so no problem with your house-cats).

Thanks for reading and writing.



Advantage nearly killed my cat. Three days after treatment (his behavior got worse and worse starting from the first day of treatment) he was listless and lying on the floor, unwilling to get up, shaking/seizures, unable to eat or even drink. I thought he would die that night - and stayed up with him all night - and took him to the vet first thing in the morning.

He had to be hospitalized and fluids given intravenously... and the first thing the vet asked was "Has he been poisoned?"

No, he wasn't poisoned by anything other than the Advantage - as it started the night I put it on him.

I would not recommend this product to ANY ONE who loves their animal - especially not for cats!


Oh - one thing I forgot to mention:

I even ran into a VET who, when I quizzed her about the effects of this poison (Advantage) said she would personally NEVER recommend Advantage to any animal.

That was the only vet I talked to who knew the scoop on just how many pets had died or were sickened by this horrible product.

It also "ate" a hole in my cat's neck where I put the original application of the product - and the hole refused to heal for weeks... bleeding and weeping - as if it had literally burned into his skin (which it had).

I will never use another commercial flea product again (whether it's vet-recommended or not). Some vets out there do know (and tell) the truth. They are rare, though. Most of them seem to care more about their sales of the product than the life of your animal, sadly.

I truly hope no one else's pet has to go through such a horrific experience - as it nearly killed my cat and broke my heart to see him like that.

As for Dawn: it may cause dryness, I don't know, or flakiness of the skin. But after that incident we did use Dawn and it killed every single flea and my cat was still healthy. It won't, however kill flea eggs. And the cat most likely won't like a bath. But it's better than having a sick animal. (Dawn will not sicken your animal; it is used on wildlife to clean their skin/feathers/fur etc. of oil after oil spills and has helped save many, many animals. Including mine - because I used it to wash off the Advantage (it is the only product recommended to remove Advantage).


Hello, Alexis,

I am sorry that you have had such a terrible experience. This is the first time I have heard of such a thing with Advantage, and I know that many people use it with no apparent problems.

Even when such an occurrence is rare, that is no consolation when it is YOUR beloved pet.

I suspect that you and your veterinarian have reported this adverse event to the manufacturer. If not, you should.

Thanks for reading and writing.


Thank you for responding - I appreciate it.

Well, we used Advantage on this particular cat three times. The first time, all he did was seem a little "off" - the second time, we noticed he was lethargic but not enough to warrant a vet visit. On the third time, he literally almost died from the product - which we couldn't understand because we only used it about once every year and didn't have problems before (other than a little odd behavior and lethargy).

Also, the dose we gave him on that last time was a SMALLER dose than we usually gave.

I don't understand why it happened but I know I can't trust it anymore.

I do thank you for your concern for my cat. You're right, it really is no consolation when it's a pet that you love.

I would love to trust Advantage again, but due to that last experience and the fact that my cat is very much loved, I just can't.

Thank you for responding to me ... have a good evening.



My dog swims a LOT. In the pond and in the pool. Will that remove advantage the same as a bath will? I know you said rain wouldn't have any effect.


Front Line Plus

@Marceia If he goes under water it is a possibility.

Jennifer Nichols

My cat nearly died from Advantage also. Our experience was almost exactly the same as Alexis'. I had used the product several times previously (more than 3 times) and it got worse each time until she had to spend several days in the vet hospital and get hydration treatments.

Another similarity that I'm noticing, that I've been wondering about, is that we both used product that was probably at least a few years old. Well, I know I did, and I assume if Alexis only applied once a year that she bought at least 3 applications which would make the last one 3 years old. I wonder if the chemical breaks down and becomes more toxic with time...


I will have to remember to check with the manufacturer on this. Most drugs are stable and effective long beyond their "expiration date". The date simply reflects the length of time the manufacturer has proven it will last.

Even when they are losing potency with age, there are apparently very few that then change into something toxic. No doubt there are instances of this, but it doesn't seem to be much of a problem. People would be dying like flies,as most hardly ever throw out old medicines. They "save a little in case I get it again later".


Can I use dog frontline on my cat if I use the correct dosage?


The only Frontline product that I am presently using is the spray. The spray is dosed in pumps per pound, regardless of cat or dog.

For the topspot, we had too many complaints about the product not giving full effectiveness for a full month. People asked if they could use a bigger size, use it more often, etc.

For dogs, we are now using Vectra 3D. With cat patients that we are seeing, we recommend Revolution. For over-the-counter sales, plain Vectra (no permethrin for ticks) made for cats.

My recollection on the Frontline is that Merial says that they are formulated in different concentrations. They did not recommend giving the dog product to cats when last I checked, but my recollection may be faulty.

If you call Merial they will certainly tell you not to.

Cats and dogs absorb things differently sometimes and it would be safest to stay with the cat product.


I have two cats who get flea treatments each month. Advantage works well on one cat, however for the other it caused complete hair loss and skin irritation at the application site (back on the neck). The fur did regrow slowly and the irritation healed. I can now only use Revolution sucessfully on the sensitive cat.


Hello, Cora,

Thanks for sharing your experience. There is no product that works for everyone.

The insert on Revolution notes that there may be hair loss at the site of application as a routine thing. We see it every once in a while.

Revolution is a go-to product for us, we really like it, but nothing is perfect for everybody.

Thanks for reading and writing.


We were told by the vet that Vectra would work for fleas on our small dogs, it didn't at all. Tried Frontline Plus, it helped but still seen 5-6 adults crawling and biting everyday-reduced the # of fleas, but didnt get rid of them. Then we finally found success when using Advantage II. The fleas are all gone, and every now and then she will bring in a hitchhiker and it will die within a few minutes of being on her. Advantage II is the best!!!!


Hello, Beth,

We have had very good results with Vectra 3-D. The Advantage II is very similar in active tick ingredient.

I am glad that you are having good results.

Did you treat the home and yard initially? If not, it doesn't matter what you use, you would keep seeing fleas.

John Doe

There's actually two very similarly named, similar products: Advantage and Advantix II. Advantage is fine for cats, but Advantix is deadly. Don't mistake them!


That is why the product is labled K-9 Advantix II. For many people "K-9" makes them think of dogs, as it should. The labeling clearly states it is not to be used on cats, as they permethrin in it is deadly to them.

Alas, people do not always read the labels, nor follow directions.


advantage just killed my cat 2 nights ago. I am devastated. The vet told me it was from the advantage. They tried to wash it off but he was too sick. He had seizure after seizure, and could not walk. He was in a lot of pain and shaking and crying. He also lost his bowels in the car on the way to the ER. It was an awful way for him to go, poisoned to death, and it is my fault because I am the one who put the advantage on him.


Hello, Aaryn,

I am sorry for your loss. This is a very surprising case. Imidacloprid (the stuff in Advantage) generally just sits on the skin, and is not absorbed. It is generally considered a very safe product.

There are other products that contain tick-control, such as K-9 Advantix II, that are usually deadly to cats. They are labeled for dog-use only, though.

If your cat was just terribly sensitive to the ingredient in Advantage, this is an incredibly rare occurrence, and there is no way you could have predicted such an outcome. You certainly shouldn't feel guilty about making a bad choice.

There was no way to predict such a thing.


Hi love your website. I have one cat and one dog a small chihuahua. I'm not really a dog person, have always had several cats but inherited the dog when the previous owner died. Can I put Advantage for cats on the dog if I use the correct dosage. I understand they have it for dogs as well but right now I don't have the money to buy one. I was hoping this might work til I get money next month. Also I only have one dose so will this at least help for the time being if I split between the cat and dog. Really can't afford it at all but like always I rob Peter to pay Paul! 😜


Hello, Karren,

The imidocloprid active ingredient is pretty safe. By the time you split a dose between two animals, it may not be enough to be effective, though. It is unlikely to hurt them.It's always best to use according to label instructions.


Hi I just started using Advantage on my cat as I have noticed the presence of flea extract on some areas on his skin. Is it ok for me to use dawn to wash off the flea extract from just his leg area (as this is where it is very bad). Or will that ruin the effectiveness of Advantage working? I would not give him a total bath nor would I get his neck area wet. Any advice would be greatly appreciated :) Thanks


Hello, Charlene,

By "flea extract" I am guessing you mean what we often refer to as "flea dirt", which is flea poop. Fleas are blood-suckers, and they poop out digested blood, which looks like black grit, kind of like pepper. If you wet it down on a white paper towel, you will see it dissolve into a reddish brown or red.

Dawn is a great de-greaser. It's not a great flea-killer. It will definitely strip off the skin oils and the Advantage along with it.

You could just rinse with water and that would take less of the Advantage. You could also give a good bath with pet shampoo before you put Advantage on the next time.

You can also use a fine-tooth flea comb to remove that debris.

Lynn Clemons

Well, I know for a FACT I DID USE ADVANTAGE II on my cat. He says in a er for pets as I write this. He began seizing this morning uncontrollably. Lethargic as well. So Bayer, after a angry call to my vet who said it was safe to use a small dog on a small cat!!! Said they have no record of ANY side affects of siezera or tremors. I think that's a crock of crap, I read too many on line complaints showing that it does. So my Archie is fighting for his life, my kids cat may not ever come home and all my vet can say is I don't know WHY he had that reaction! Bull!!


Hello, Lynn,

If you used the Advantage II for cats, it contains imidocloprid (the flea killer), which is pretty much non-toxic to mammals, and pyriproxifen (sterilizes flea eggs, should they live long enough to bite the cat and lay eggs), which is also generally considered non-toxic.

Certainly there are individuals who cannot tolerate certain drugs or chemicals, even when the dose is correct (according to safety testing done before the drug is approved for marketing). There people who cannot take an aspirin, which is pretty harmless for most of us.

If the cat had no exposure to any other compounds, and this is purely a reaction to the application of the Advantage II, that would be a very rare thing. Millions of doses are sold and used without a problem.

This does not mean it is impossible that the product is what caused your cat's problem. There are what are called "idiosyncratic reactions", meaning that it is unique to that individual. For other individuals, the compound is okay. For this individual, other compounds are okay-- it's not an unhealthy animal.

These are uncommon, and they are unpredictable.

The most common scenario that I see producing what you describe is where a well-meaning owner makes a mistake and applies a dog-only product containing permethrin to the cat.

We are also seeing more seizures from toxicity from the new mouse poisons that contain bromethalin. These are very tough poisons that cause brain swelling and seizures, and there is no antidote.

I haven't seen any controlled studies about how many woozy mice the cat would have to eat to get poisoned without eating the baits directly themselves. There are case reports of barn cats who would be consuming large numbers of mice that apparently have gotten enough bromethalin to cause seizures.


I wonder if I can give my dogs a bath and use a dog shampoo after using frontline


Hello, Patty,

I would not bathe for at least two days before or after applying Frontline. It distributes itself into the skin oils, and then down into the oil glands at the base of each hair shaft.

If you have just bathed the dog, that oil layer has been disrupted, and the product won't spread properly.

If you don't give it a couple of days to spread after application, you will wash off a lot more of it.

Bathing more often than once weekly will diminish the products effectiveness, but it is more bath-resistant than a lot of products.

Unfortunately, while I really liked Frontline, I had a lot of clients complaining that it wasn't working as well for them as it used to, so we are now using a product called Vectra 3-D.

Any topical product is going to come off if you bathe two or three times a week.


My shih tzu has advantage on and is now itching worse than wit fleas. I used a steroid spray to calm it which left her hair greasy. Any suggestions


Hello, Sherry,
Most dogs tolerate the product very well, but it is possible to sensitive to anything. I'd just give the dog a bath in mild soap to remove the product.

Patrice Bryan

My cat had a very severe reaction to Advantage Multi about four years ago. Same thing--seizures, panic, then severe lethargy. He was in the hospital for two days getting fluids. The vet was unwilling to determine Advantage Multi as the problem, but noted that it does say on the insert that cats with upper respiratory issues due to herpes can have severe reactions. I didn't read the fine print. I'm about to apply Revolution and am very very nervous. I'll post how it goes. My vet now says they stopped carrying Frontline because it seems to have stopped working.


Hello, Patrice,

I use Revolution as my first choice in cats, and have not used the Advantage Multi in cats. We use a LOT of Advantage Multi in our outside dog patients, and have had no problems with it there.

Revolution will occasionally cause some skin irritation, even to the point of temporary hair loss. We see that only rarely, and have never seen anything more severe than that.

Frontline used to be great, but we just had too many clients asking if they could use it more often or use a bigger size, as it wasn't working "like it used to".

On dogs we use Vectra 3D now, and we have been happy with that.


I have treated my cat with Advantage ll and my dog with K9 Advantix ll. I have recently heard how well Vectra works in getting rid of fleas. Can I give Vectra (Vectra 3D for the dog and Vectra for cats) to each animal 2 weeks after being treated with the Advantage and Advantix? Or, do I need to wait 2 more weeks to give the Vectra? I don't want to poison my furry family. I am vacuuming and treating the environment, but am still seeing live fleas on the treated cat.


Hello, Tara,
I understand your concerns. I would not add the Vectra until the four weeks are up.

It is possible that the Advantage is working better than you think. It won't keep them from getting on the pet, just kills them after they get there.

If the fleas you see are big and brown, they have been feeding for a while and the product is not working.

If they are tiny and black, they just arrived from the contaminated environment and have not been on the dog long.


Hi, thanks for a very informative site.

On October 30, I switched from Frontline to Vectra3D on my 17 lb. Bichon mix. I did not bathe her prior to application and waited 4 days afterward to do so, because the application site became very dirty and gray(she is white,)

It appears that the Vectra is not working. I called the company and they said I had likely washed it away. They recommend I wash my dog today, November 7, with Dawn, and when she is thoroughly dry, reapply the product.

Is this good advice?




Hello, Cathy,

I have had very good luck with the Vectra. It is important to get it down underneath the hair, directly on the skin. You also need to apply it in a "stripe" from the top of the rump up to the shoulders.

Dawn is a great de-greaser. By bathing with it, you will strip the skin oils, which should get the rest of any residual Vectra, thus eliminating any likelihood of overdosing when you re-apply the product.

So, if the company advised you to do that, that's what I would do.


How long after applying Advantage II for large cats do you have to wait to comb or brush your cat?


Hello, Paul,
Once it is dry, you should be fine. It usually just takes a couple of hours. Wait four to be safe.


I used advantix on both my Jack Russels. Soon after that I noticed they are both twitching their ears like it is irritated. They were not doing it before application. Should I be concerned?


Hello CC,

Sorry I didn't get to see this until a day later. The good thing about this product is that it can be washed off if there is a persistent reaction.

If you are seeing more signs of skin irritation, then I would bathe the dogs.

It is common after application of these products for the dog to show brief signs of annoyance from the smell, and sometimes from the sensation on the skin. Some dogs may even experience a small spot of hair loss at the site.

If you have repeated problems, then I would look at a different product. There are lots of good choices. You might look at a systemic product like Nexgard (you eat it and the stuff stays in the bloodstream for a month - fleas and ticks suck blood and die with their first meal).


I need to use advantage !! on my dogs, but they had a bath with flea shampoo about 7 days ago. How long do I have to wait to use the advantage. If I use it now will the shampoo make the advantage ineffective?


Hello, Julie,
You can use the Advantage as soon as the dog is dry, so 7 days is plenty of time to get dry.

The shampoo has been rinsed off, so will have no effect on the Advantage.

Scrubbing with soap and water will remove half the Advantage per bath. Thus, you can probably keep decent flea control if you bathe only one time between applications. You can bathe twice a month, if the first bath is before you re-apply the Advantage.


In error my daughter's 3 cats received their application of Front Line two weeks early. This was not intentional, and they have done well with regular applications each month. Cats are around 6 years old, no health problems and maybe a little on the plump side. It has only been a few hours since application. Should we try to scrub it off of them?


Hello, Sam,
Sorry to be so late replying, but I have been out of town.

Frontline is extraordinarily safe, and would have been very unlikely to cause any problem in the scenario you describe.

In a situation like this, you should call the manufacturer's hotline. The number is on the package.

If your local veterinarian is not available, the animal poison control center is available 24/7 for a fee.

Dr.Google is not a reliable resource in an emergency (Which this fortunately was not).

James B

Im way late to this thread but I have been using Advantage (original, not Advantage 2) on my cat and 4 dogs for at least a decade. None of them ever had a bad reaction. Ive always used it for 2 months in the summer and it always kills the fleas very quickly right after first application. I usually do the 2 application a month later just to make sure extra hitch hickers arent brought into the home from the dog park. I love it and will probably give it to them until they stop manufacturing it. Then i'll have to decide between A2 and Frontline.

Becky Marshall

I have a new cat that I rescued 3 days ago. She is very emaciated and has a bad case of fleas. The vet put Advantage Multi on her, but 48 hours later she is still showing live fleas. I just want to know when it is safe to bring her into the house (she is in the garage now). I have two other cats (both treated with Advantage), and lots of upholstery and rugs/carpet that I do not want infested with fleas. Also, if I can't use shampoo on her so as not to wash away the Advantage, would rinsing her with warm water help get some of the flea dirt, fleas and general dirt off of her? And is this a good idea or a bad one? Thanks.


Hello, Becky,
Ideally, we would have washed her first. I would recommend that you get a flea-comb. This is a very fine-toothed comb that will catch fleas, and help remove the flea-droppings.

If the area has not been previously infested, you should not be having live fleas at this point. If the fleas are tiny and black, they are new fleas that are coming from the environment. If they are bigger and brown, they have been feeding on the cat, and the product is not working as it should.

If you can make that differentiation, you will know whether to treat the area where the cat is housed, or to speak to your veterinarian and get some supplemental flea control (like a Capstar tablet) before bringing her in.


Hello, I hope this isn’t a dumb question but I put Advantage ll on my cat the 18th of December and tonight the 30th of December I gave her a bath with dawn to get it off the flea dirt that seems to be falling off and also remaining on her. Do I need to reapply the advantage or should she be still covered by the advantage till the next Treatment in a few weeks? Thank you for your time


Hello, Lyndsy,

I think some of that depends on how hard you scrubbed. The company says that one bath usually removes about half the stuff, and the half remaining should be effective for another two weeks.

On the other hand, Dawn is a very effective degreaser and takes off more skin oil and stuff than a shampoo designed for pets.

I am not a fan of Dawn for pet-bathing unless you have been in an oil spill.

I would monitor the cat by using a flea-comb (fine toothed comb) to see what your flea population is doing. If they are coming back, then it is safe to reapply the Advantage.


Hi I used sentry all natural flea and tick for indoor cats , I read a bunch of horrible reviews , got nervous as he’s my first cat and washed him with dawn , he hates baths so I tried my best , problem is he still stinks like the medicine , when I pet him the smell is on my hand also , how long will that last ?


Hello, Liz,

I cannot give you a definite answer. My wife is big into these essential oil things, and I can tell you that they definitely work as a husband repellent. Don't know about fleas.

By the next morning after her shower, I am able to return to her side.

I would wait 24 hours and do one more bath with the Dawn.

Normally I'm not a fan of Dawn, but it's a great degreaser, so should be good for removing oils.

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