Updated March 2015

What the best flea treatment does

  • Works quickly and reliably. The best flea treatments should work quickly enough that your pet will find relief within a short period of time. If the first one you try doesn't work, try something else.
  • Kills adult fleas, eggs and larvae. Some medications and treatments kill adult fleas only, so you may need to re-treat fairly often, or combine them with a second flea treatment to avoid re-infestation.
  • Causes few side effects. Most flea treatments have potential side effects, though those are mostly minor. However, others could be life threatening to certain animals. Cat owners in particular should avoid products containing permethrin and other pyrethroids.
  • Is easy to use. "Spot-on" topical treatments are quick to apply to a pet's neck or back, while tablets can often be tucked into a treat like cheese or peanut butter.

Know before you go

Talk to your vet. Your vet may have specific recommendations for products he or she thinks are the most appropriate. This is especially important in the case of pets that are weak, older, medicated, sick, pregnant or nursing, or that have previously had an adverse reaction to a flea control treatment. Additionally, some products are not suitable for puppies and kittens.

Check your pet's weight. All flea control treatments are packaged according to the pet's weight. Don't try to guess your pet's weight or buy the wrong dosage because it's cheaper. You might end up with a dosage that's too low to kill the fleas or, worse, one that's too high and causes serious side effects.

Read the directions. Before you buy a product, take a look at the application instructions and make sure you understand them. Even if you have used the product before, review the directions to make sure they haven't changed. Many reported illnesses in cats and dogs from flea control products are due to misuse. Be especially careful not to use flea control treatments designed for dogs on your cat, or vice versa. Permethrin, a pesticide found in some topical dog treatments, can be lethal to cats.

Choose the right treatments. Don't waste your time with flea shampoos, dips, sprays or powders. Vets generally agree that these products are ineffective at best and toxic at worst. The same goes for "natural" remedies like essential oils and garlic.

Buy your flea remedies from your vet or from a reputable retailer. Many products sold online, and sometimes even in stores, are counterfeits that may be ineffective or harmful to pets. Counterfeit versions of Frontline Plus are particularly common.

Are generics safe? Frontline and Frontline Plus are available in generic formulas at savings ranging from a little to a lot. Experts say to avoid the cheapest generics as they won't provide the same level of protection as better options. Also, though they might use the same active ingredients, the inert ingredients may differ, and that can be the difference between a treatment your pet tolerates well, and one that might irritate. Consult with your vet if you are unsure of any flea treatment.

Be wary of new products. That's the advice of The Whole Dog Journal, which adds that you shouldn't feel pressured to change if a flea treatment that you've been using is continuing to work well. In addition, newer flea treatments have been subjected to less "real world" testing, which can often reveal shortcomings or hazards that lab testing fails to turn up. "We suggest that pet owners stick with older products until the safety of new ones has been established," says Nancy Kerns, editor of Whole Dog Journal.

If you don't see it, ask. Pet stores may not keep all their flea remedies on the same shelf. Some of them may be locked up in a separate case to prevent theft. If you don't see the one you want, ask an employee where to find it.

Treat the whole house. Money spent on a flea treatment is wasted if you don't get the fleas out of your house. Vacuum carpets and upholstery daily, and discard the vacuum bag (outside the house) right away so fleas don't escape. Also, wash bedding, and wipe floors and furniture.

Keep your eyes open. After treatment, monitor your pet for any signs of a harmful reaction. Be prepared to contact your vet if necessary. Also keep an eye out for fleas that survive the treatment. Some products can be re-administrated right away while others should not be. Follow manufacturer instructions and talk to your vet about additional treatment.

Know what to expect. Some flea treatments work almost immediately, some take a day or more for effects to be seen. Frontline and Frontline Plus work by over stimulating a flea's nervous system, something that's often mistaken for an increase in fleas by anxious pet owners.

Elsewhere in this report:

Best Reviewed Flea Control Treatments: Whether you -- and your pet -- prefer a spot-on treatment or a pill, these are the flea control products that experts and users say kill fleas dead. All are effective, and safe.

Best Flea Treatments: Spot-on flea-control treatments are applied to the skin. Reviews say they are the most effective way to rid your pets of their pests, and these are the top choices.

Best Flea Medications: Oral flea medications are safer and less traumatic to some pets, but not always as effective as spot-on flea treatments. These are the ones that experts and users say are best.

Our Sources: Where can you find the best reviews of flea treatments? Our editors used these reviews and guidance from veterinarians, pet experts, scientists and everyday pet owners in compiling this report.

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