Both products kill fleas and ticks on your pet, however our most advanced formula FRONTLINE Plus also stops flea eggs from hatching and infesting your home.

Once applied, FRONTLINE Plus® / FRONTLINE Tri-Act® / FRONTLINE® Spot On is stored in the sebaceous glands in your pet's skin and spreads over the whole body surface with their natural oils. Fleas and ticks are killed through contact with your pet's skin and coat so they do not need to bite to be killed.

If you can still see fleas on your pet after treating them, it would be natural to think that the treatment isn’t working. However, no product can repel fleas from jumping onto your pet so it is normal to continue to see fleas after treatment as your pet can pick up new fleas from the environment at any time. Moreover, if you are fighting a home infestation, it is highly likely that you will see fleas on your pet for 3 months or more as it can take this long to get rid of the infestation. Don't worry, if you see fleas for several days in a row, today's flea is not the one you saw yesterday. Your treated pet is a flea-killing machine and any fleas jumping on will be killed within 24 hours with FRONTLINE Plus® and FRONTLINE® Spot On, or within 6 hours with FRONTLINE Tri-Act®. If you have any concerns, please contact our technical services team at petsUK@boehringer-ingelheim.com, or your veterinary surgeon.

Yes, FRONTLINE Plus® / FRONTLINE® Spot On can be used on any breed of cat and dog, including collies and other herding-breed dogs which can sometimes show a sensitivity to some parasite treatments.

FRONTLINE Plus®, FRONTLINE Tri-Act® and FRONTLINE® Spot On have an exemplary safety profile and adverse reactions to the treatments are very rare. If you believe your pet has experienced any adverse reactions after use of FRONTLINE Plus®, FRONTLINE Tri-Act® or FRONTLINE® Spot On, please contact our technical services team at petsUK@boehringer-ingelheim.com, or your veterinary surgeon.