Today we are going to take a long hard look at Seresto flea collar side effects.

It is all good and well that flea and tick collars protect your pets, but what are the Seresto collar side effects and how will they actually affect your pets? Can Seresto flea collar side effects be harmful to your dog?

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Hunting for the best flea and tick collar can be hard work (make sure you visit our Seresto dog collar reviews or our Seresto cat collar reviews). The market is saturated with choice and Seresto is yet another company providing a quality product. Whether you are looking for a flea collar for cats, or a flea and tick collar for dogs, the Bayer Seresto flea and tick collar choice is impressive!

What are Seresto collar side effects?

There is absolutely no doubt that a Seresto collar or Seresto dog collar is an excellent way to manage fleas and ticks but how does Seresto work? Is Seresto safe for our pets? It’s a completely natural question to have, because a Seresto collar is an external product that we are putting on a beloved pet, and we naturally want them to be safe.


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So what are the side effects of Seresto flea collars? A close look at their product brochure shows that the Seresto side effects are pretty lethal to fleas and ticks. The Seresto collars are an 8 month flea collar and repel and kill ticks for 8 months (if used correctly). Their targets include deer ticks, American dog ticks, brown dog ticks, and lone star ticks. Fleas on the other hand have an expected life of just 24 hours once the collar is applied and only 2 hours if they are a new infestation arriving on the animal. Wouldn’t you hate to be a flea or tick!


seresto collar side effects seresto collar side effects seresto collar side effects

How does the Seresto collar work?

But what is it that has the power to act in such a way? And can the Seresto flea and tick collar side effects be a concern for our animals?

Taking a closer look at the Seresto collar safety brochure and the Seresto collar warnings (click to read more in our Seresto collar reviews) and we see the active ingredients are listed as Flumethrin and Imidacloprid.


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Active Ingredient Side Effects

Flumethrin is a pyrethroid insecticide that is used externally in veterinary medicine against parasitic insects and ticks on cattle, sheep, goats, horses, and dogs. Imidacloprid on the other hand is an insecticide which acts as a neurotoxin which act on the central nervous system of insects and has a very low toxicity to mammals.

But what does this mean for our pets and are there Seresto side effects to be concerned about? Well, yes and no. The real answer depends entirely on your animal and unfortunately it is hard to truly assess Seresto safety.

For the majority of animals, if there are any side effects of Seresto collar use, they will be minimal. Seresto dog collar side effects can include localised skin irritation, hair loss or rubbing from the physical collar. Such issues that are mirrored by Seresto cat collar side effects.

Issues arise when you place your cat flea collar or tick collar for dogs on an animal that is allergic to the active ingredients. Seizures, diarrhea and vomiting are possible, however we must stress that these are extreme cases. For the majority of animals, Seresto flea collars are both safe and effective but how can you know if your pet is one of the unlikely allergic animals? Unfortunately there really isn’t any way to know in advance if your pet is allergic. Close observation for a period of time after its application will certainly help you pick up on Seresto collar side effects before they get too serious.

Dog flea collar side effects

Looking at the effect that a Seresto flea collar for dogs may have, starting with Flumethrin side effects. If your dog does react to flumethrin, Seresto collar for dogs side effects may be varied. Side effects may include: local dermatitis (skin irritation) with pruritus (itching) and erythema (red skin). Symptoms will depend on the dose, the formulation, and the kind of contact (skin, inhalation, ingestion etc). Flea and tick collar side effects of this nature are not common however.


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Side effects from Imidacloprid use can include fatigue, convulsions, lethargy and difficulty breathing. Unstable gait and tremors can also occur, but again, are rare symptoms and not common side effects of flea collars.

Cat flea collar side effects

Seresto flea collar for cats side effects are similar to the Seresto collar for dogs side effects. So, if using Seresto for cats is accordance with the instructions, Bayer Seresto collar side effects should be minimal. Compare the effectiveness of using flea collars on cats against any possible side effects. Which outcome is more valuable?


As with anything in life, a treatment is only useful if it is effective. Not treating for fleas and ticks will cause issues that far outweigh those possible using a Seresto flea collar. The purchase of a Bayer flea collar will provide many months of protection. Furthermore, Seresto collar side effects are unlikely to cause any significant concern.

For cat lovers, the Seresto collar for cats is an excellent choice. Your cat will enjoy many months of protection and you need not worry about those annoying fleas. In our opinion this makes it the best flea collar for cats.

For dog lovers the Seresto flea and tick collar for dogs is a quick, easy and affordable choice. Therefore, it is a decision that will keep your pooch, happy and healthy, and make you one very happy owner!