No, the U.S. Environmental Protection Agency (EPA) has not cancelled Seresto, a topical flea and tick prevention for dogs and cats. On July 29th of 2020, the EPA announced that it is taking action in response to reports about the safety of Seresto collars for pets due to exposure to the active ingredient (imidacloprid) contained within them.

The EPA has requested that Elanco Animal Health provide additional information regarding imidacloprid and its use in flea and tick products like Seresto collars. The EPA will consider potential risks associated with these products – both environmental and human health – based on this new data as they are evaluating current regulations related to the safe use of such products.

The EPA will also review any new information provided by Elanco Animal Health that could help improve risk assessments of imidacloprid’s use in pet flea and tick treatments. This review will be focused on pet health, environmental impacts, and any potential effects that may arise from using labeled Seresto product concentrations over extended periods of time on dogs or cats with multiple chemical sensitivity issues. For now, all existing regulations for Seresto collars remain in place until further notice from the EPA.

What Is Seresto?

Seresto is a flea and tick collar designed by Bayer Animal Health. It works by releasing an active ingredient, imidacloprid, as vapor through the collar that comes in contact with the animal’s hair and skin. The vapors are then inhaled or absorbed through the skin and work to kill adult fleas and ticks. In addition to killing adults, Seresto also helps prevent flea eggs from hatching and stop ticks from latching on to the host animal altogether.

Seresto has been effective at preventing flea and tick infestations without having to apply chemical-based topical treatments every month. Many pet owners sing its praises for their four-legged friends, but unfortunately it looks like this beloved product may not be available for much longer due to recent EPA regulations.

Why Was a Cancellation Request Issued?

The Environmental Protection Agency (EPA) requested the cancellation of Seresto, an insecticide specifically used to treat animals, due to toxicity concerns. Specifically, the EPA determined that the combination of two active ingredients in Seresto, flumethrin and imidacloprid, posed risks to wildlife and people.

The EPA’s request for cancellation was supported by studies indicating that when animals were exposed to these two chemicals together, it caused them health problems. Studies also showed that flumethrin and imidacloprid can accumulate in the environment and contaminate water and soil. Additionally, some evidence indicated that exposure to flumethrin could cause reproductive or developmental issues in both humans and animals.

Due to these toxicity concerns, the US EPA recommended immediate action and issued a request for cancellation of products containing the two compounds—marking the first time the agency had requested such a move since 1994. The manufacturers have since agreed to comply with the requested changes.

What Formulations Are Affected?

The EPA has cancelled several formulations of the Seresto flea and tick collar for dogs. Specifically, the products affected are collars that contain high quantities of active ingredients known as deltamethrin and flumethrin. The company’s website states that all Seresto collars are safe for pets when used as directed on their label.

However, certain types of collars may have higher levels of active ingredients than is recommended by the EPA’s label requirements. The heightened concentration in these kinds of collars could lead to potential health risks for pets, so it is important to make sure you are using an approved product when purchasing a Seresto collar.

EPA also noted that affected forms had “inadequate warning statements concerning risks associated with continued use,” so it is advisable not to exceed the time period or saturation indicated on the product label. Additionally, if you find your pet in an area heavily infested with ticks and fleas, talk to your vet about potentially stronger treatments, such as spot-on treatments or other medications.


The EPA requested that certain formulations of Seresto be canceled over safety concerns. However, alternative products are available on the market which have been deemed less likely to pose human or pet health risks by EPA regulators.