Keeping My Animals Happy

Three Reasons Why Your Flea Medicine Doesn't Work Well Enough

by Reginald Ruiz

Keeping fleas off of one's cat and dog is typically a pet owner's first priority, since these pests can be irritating to humans, too. Even people who apply anti-flea medication on a regular basis may notice that there are still plenty of fleas. If you're bothered by the amount of fleas you're noticing, here are three reasons why your medication might not be working properly.


Flea medications contain an anti-parasite neurotoxin that's lethal for fleas while safe for pets. However, not all fleas are created equally. Fleas can be born with genetic variances that give them a resistance to the poison that you're using to try and kill them. As fleas survive the medication and procreate, they continue to pass these genes down until you end up with more fleas that are resistant to your medication than fleas that die when exposed to it. In this scenario, the only thing you can do is change medications to something that will work.

Application Process

Another common problem people have is not getting down to the skin when they apply their anti-flea medications. If some or all of the medication isn't coming into contact with your pet's skin, then it's not going to do its job properly. In order to work, the medication has to be absorbed into your cat's skin to keep fleas at bay. If it is absorbed by your pet's fur, it won't get the job done.

Finding a part in a pet's fur can be tricky, especially if it's thick or long. In this instance, using a trimmer to make a small bald patch on the back of your pet's neck can help you to more easily get the medication in contact with their skin.

Type of Medication

Another problem might be the type of medication you're using. Some anti-flea products kill fleas through their entire lifecycle, from the egg to the adult flea. Others, however, only kill adult fleas. This means that any eggs that were on your pet when they were medicated might survive and hatch into adult fleas once the medication isn't effective. Alternatively, it could just be allowing fleas to live long enough to make it off your pet and instead survive in your home.

If your cat or dog has fleas, it's time to re-evaluate the medication you're using and how you're using it. If you're uncertain where the problem lies, talk to your veterinarian to find out more. For more information, visit websites like