9.1
Score
Seresto
Seresto Flea & Tick Collar for Large Dogs 8-Month
★★★★★7234 reviews
The gold standard in flea and tick prevention. One collar provides 8 months of continuous protection — no monthly applications, no mess, no remembering doses.
$59.98
Independently tested · Why trust us?
Pros & Cons
✓ What We Love
- Full 8-month protection from a single collar
- Kills and repels fleas and ticks on contact — no biting required
- Non-greasy, odorless technology
- Water-resistant for swimming and bathing
✗ Things to Consider
- Premium price at ~$60 (but cheaper per month than topicals)
- Reports of skin irritation in some sensitive dogs
- Counterfeit collars are a problem — buy from authorized retailers only
Who Should Buy This?
- ✓Dog owners in tick-heavy regions wanting set-and-forget protection
- ✓Owners tired of monthly topical or oral treatments
- ✓Active dogs who swim or get bathed frequently
Compare Prices
Prices updated regularly. Click to check current live prices.
Full Specifications
| Protection Duration | 8 months |
| Active Ingredients | Imidacloprid 10%, Flumethrin 4.5% |
| For Dogs Over | 18 lbs |
| Water Resistant | Yes |
| Kills | Fleas, Ticks, Flea Larvae |
| Collar Length | Adjustable up to 27.5 in |
Frequently Asked Questions
Seresto is EPA-registered and has been used on millions of dogs globally. However, the EPA received incident reports in 2021 prompting ongoing review. Most dogs tolerate it well, but monitor for skin irritation, lethargy, or vomiting when first applied.
Buy only from authorized retailers like Chewy, Petco, PetSmart, or your vet. Verify the tin packaging has the Bayer/Elanco logo. Amazon marketplace sellers may carry counterfeits — buy from the official Amazon listing only.
Yes, Seresto is water-resistant and remains effective after swimming or bathing. However, frequent swimming (more than once a month) may reduce effectiveness to about 5 months for ticks.
Seresto kills existing fleas within 24 hours and ticks within 48 hours of application. It begins releasing active ingredients as soon as you put it on your dog.
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Reviewed by Dr. Sarah Mitchell
Last updated: 2026-03-18 · How we test
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