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Seresto Cat

This page contains information on Seresto Cat for veterinary use.
The information provided typically includes the following:
  • Seresto Cat Indications
  • Warnings and cautions for Seresto Cat
  • Direction and dosage information for Seresto Cat

Seresto Cat

This treatment applies to the following species:
Company: Bayer Animal Health

For 8-month prevention and treatment of ticks and fleas on cats and kittens 10 weeks of age and older.

● Kills and Repels fleas and ticks.

● Repels and kills ticks, including Deer ticks (vector of Lyme disease and anaplasmosis), American dog ticks (vector of Rocky Mountain spotted fever, cytauxzoonosis and ehrlichiosis), Brown dog ticks (vector of ehrlichiosis, anaplasmosis, babesiosis, and Rocky Mountain spotted fever), and Lone Star ticks (vector of cytauxzoonosis and ehrlichiosis).

● Prevents tick infestations within 48 hours after application.

● Quickly kills fleas on cats within 24 hours and continues to prevent infestations for 8 months.

● Treatment with Seresto kills fleas that may vector bartonellosis (Bartonella henselae), tapeworm infections (Dipylidium caninum), feline infectious anemia (Mycoplasma spp.), and rickettsiosis (Rickettsia felis).

● Re-infesting fleas are killed within 2 hours with protection against further flea infestation lasting 8 months.

● Kills and repels fleas before they lay eggs.

● Seresto aids in control of flea larvae in the cat’s surroundings following contact with a Seresto-treated cat.

● Bayer Polymer Matrix ensures that both active ingredients are continuously released in low concentrations.

● Make sure to replace the collar after 8 months for year-round tick and flea pest prevention.

● Light reflectors for added visibility in the evening and at night.

Active Ingredients

% by Weight









* Trans Z-1/trans Z-2 ratio: max 66% trans Z-1 and min 34% trans Z-2







Have the product container or label with you when calling a poison control center or doctor, or going for treatment.

● For CONSUMER QUESTIONS, call 1-800-255-6826.

● For medical emergencies involving HUMANS or ANIMALS, call 1-800-422-9874


It is a violation of Federal Law to use this product in a manner inconsistent with its labeling. Do not contaminate feed or food.


One collar per animal to be fastened around the neck.

Remove collar from protective bag directly before use. Unroll collar and make sure that there are no remnants from the plastic connectors inside the collar.

Insert end of the collar through the buckle. Adjust the collar around the animal’s neck without tightening it too tight or leaving it too loose. As a guide, it should be possible to only insert 2 fingers comfortably between the collar and the neck. Pull excess collar through the loop(s). Collar length of greater than 1 inch (2 cm) beyond the loop(s) should be cut off unless it is on a growing kitten, where some additional length may be needed for adjustment as the animal grows.

After application of the collar, three reflector clips may be fixed permanently to the collar to increase the animal’s visibility in the dark. Take the clips out of the bag. The clips should be evenly distributed on the non-overlapping part of the collar. The clips are correctly applied when a clicking sound is heard. For safety reasons once the reflectors are fixed to the collar the clasp closes permanently and cannot be re-opened.

The collar should be worn continuously for the 8 month protection period. Check periodically and adjust fit if necessary, especially when kittens are rapidly growing.

This collar is designed with a release mechanism. In the unlikely event of a cat being trapped, the cat’s own strength is sufficient to widen the collar to allow for quick release.

Replace the collar after 8 months for optimal flea and tick protection.


Kills fleas which may cause flea allergy dermatitis (FAD) or flea bite hypersensitivity (FBH).

Seresto kills existing fleas on cats within 24 hours. Reinfesting fleas are killed within 2 hours with protection against further flea infestation lasting eight (8) months. Pre-existing pupae in the environment may continue to emerge for six (6) weeks or longer depending upon the climatic conditions. Seresto aids in control of flea larvae in the cat’s surroundings following contact with a Seresto-treated cat.

Ticks already on the cat prior to treatment may not be killed immediately after collar application and may remain attached and visible. At the time of application remove ticks already on the cat. The prevention of infestations with new ticks starts within 48 hours after application of the collar.

Re-infesting ticks are repelled and/or killed as quickly as 6 hours.

Occasionally scratching may be observed in animals that are not used to wearing collars in the first few days after fitting. Ensure that the collar is not fitted too tightly. Slight hair loss and mild skin reactions due to the mechanical irritation of the collar may occur at the application site which usually recover within 1 or 2 weeks without the need for collar removal. For further guidance regarding individual animal sensitivities, see information below.

In case of loss of collar, a new collar may be applied immediately. Do not attach a leash to the collar as this may cause breakage.

Keep the collar in the bag and in the outer packaging until use. As with any pesticide product, do not allow small children to play with the collar or reflectors, or to put them into their mouths. Avoid contact with eyes, skin or clothing. Wash thoroughly with soap and cold water after fitting the collar. People with sensitivity reactions to the ingredients of the collar should avoid contact with the collar. Choking hazard. Contains small parts. Do not place collar or reflectors in mouth. Not intended for use on humans.

For external use on cats only. Do not use on other animals. Do not use on kittens under ten weeks of age. Do not get this product in cat’s eyes or mouth. As with any product, consult your veterinarian before using this product on debilitated, aged, breeding, pregnant, or nursing animals. Individual sensitivities, while rare, may occur after using ANY pesticide product for pets. Rarely, mild application site reactions may occur, such as scratching, redness and hair loss, which usually recover within 1 to 2 weeks without the need for collar removal. In some cases, a temporary collar removal and bathing may be recommended until symptoms have disappeared. In very rare cases, application site reactions such as dermatitis, inflammation, eczema or lesions may occur. In these instances, collar removal is recommended. If signs persist, or become more severe, consult a veterinarian immediately.

If your animal is on medication, consult your veterinarian before using this or any other product. If your cat is experiencing an adverse event, contact your veterinarian and call 1-800-422-9874.

The patented continuous release technology ensures that both active ingredients are slowly and continuously released in low concentrations from the collar towards the animal. This avoids peak concentrations and ensures that concentrations of both active ingredients are present in the cat’s haircoat during the entire efficacy period. The active ingredients spread from the site of direct contact over the skin surface.


Do not contaminate water, food or feed by storage or disposal.

Do not use container for food storage or other purposes.

Pesticide Storage: Store in original unopened container in a cool, dry place that is inaccessible to children.

Container Disposal: Dispose of pouch and expired collar in trash. Outer container may be recycled or disposed of in trash.


Bayer HealthCare LLC, Animal Health Division, warrants that this material conforms to the chemical description on the label. TO THE EXTENT CONSISTENT WITH APPLICABLE LAW, BAYER MAKES NO OTHER EXPRESS OR IMPLIED WARRANTY, INCLUDING ANY OTHER EXPRESS OR IMPLIED WARRANTY OF FITNESS OR MERCHANTABILITY, and no agent of Bayer is authorized to do so except in writing with a specific reference to this warranty. To the extent consistent with applicable law any damages arising from a breach of this warranty shall be limited to direct damages and shall not include consequential commercial damages such as loss of profits or values, etc. The reflector clips contained herein are only meant to be used in combination with the specific collar and have been tested only for such use and purpose. To the extent consistent with applicable law, Bayer excludes liability for any misuse and use other than in combination with the specific collar as described in the packaging insert.

EPA Reg. No. 11556-155

Manufactured For Bayer HealthCare LLC, Animal Health Division, P.O. Box 390, Shawnee Mission, Kansas 66201, USA

Made in Germany

Bayer, the Bayer Cross and Seresto are registered trademarks of Bayer.

© 2018 Bayer


Regulations for product use are established by country. Information contained on this site pertains only to the United States of America, and is not intended to provide adequate information for product use. Before using or dispensing any product, read and carefully observe the label directions.

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Customer Service:   317-276-1262
Technical Service:   800-428-4441
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Copyright © 2023 Animalytix LLC. Updated: 2023-05-30