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The Seresto Flea & Tick collar has been linked to pet deaths, tens of thousands of injured animals, and hundreds of harmed humans, according to documents released by the US Environmental Protection Agency.

Seresto collars are manufactured by Bayer and were introduced to the market in 2012. They are now among the most popular flea and tick collars in the country.


The collar works by releasing small amounts of pesticides (imidacloprid and flumethrin) onto the animal for months at a time. The pesticide is supposed to kill fleas, ticks, and other pests but be safe for cats and dogs. That hasn’t been the case, however.

USA Today reports that the EPA has received more than 75,000 incident reports related to the collars, including nearly 1,000 involving human harm.

What’s even more disturbing is that the EPA hasn’t done anything to warn the public about the dangers of the Seresto Flea & Tick collars, despite many angry, grieving pet owners begging them to do just that.


Karen McCormack, a retired EPA employee, said the collars have the most incidents of any pesticide pet product she’s ever seen. “The EPA appears to be turning a blind eye to this problem,” Karen told USA Today. “I think this is a significant problem that needs to be addressed sooner rather than later.”

Signs your pet may be having an adverse reaction to their flea & tick collar include seizures, vomiting, loss of hair, and lethargy.

Pets aren’t the only ones the Seresto collars have harmed. Between 2013 and 2018, 907 incidents were reported with humans, according to a September 2019 EPA assessment of human health risk.


Victims include a 12-year-old boy who slept in a bed with a dog wearing a collar started having seizures and vomiting. He had to be hospitalized. Another report is of a 67-year-old woman who also slept with her collar-wearing dog and started having heart arrhythmia and fatigue.

Even though the EPA claims to be monitoring the situation, it’s clear there are still safety concerns surrounding the infamous Seresto collars. If your pet is wearing one of these collars, keep a close eye on them or replace the collar with a safer one.

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