Advantage II Large Cat Vet-Recommended Flea Treatment & Prevention | Cats Over 9 lbs. | 4-Month Supply
Advantage
Best for
Best for cats
Amazon rating
Amazon aggregate, one input among many in the Verdict Score
Based on 1 trusted source
Current price
$41.59
Updated May 14, 2026 · 1 min read
Sources behind this verdict
10 reviewers weighted by source trust
The consensus
What reviewers found
Synthesized across the trust-weighted source mix below.
Across the reviewers we read, Advantage II is the default OTC topical recommendation for cats. On r/Pets and r/CatAdvice, owners repeatedly cite vet recommendations for the product, and verified-purchase reviewers at Walmart and Chewy describe fleas dying within hours and scratching stopping within a day. The active ingredient is formulated specifically for felines, which is the central distinction from cross-species dog products that can be toxic to cats.
What reviewers liked
- Vet-recommended status corroborated across r/Pets and r/CatAdvice threads
- Cat-specific formulation — reviewers report no serious adverse reactions across 78,000+ Amazon reviews
- Kills fleas within 12 hours per manufacturer claims, with verified-purchase reviewers confirming fast action
- Multi-month supply lowers per-dose cost versus prescription alternatives
Where it falls short
- r/CatAdvice users report doses sometimes don't last the advertised 30 days
- Does not cover ticks — fleas only
- r/Pets users in resistance-heavy regions report needing to escalate to prescription products
- Cat must weigh over 9 lbs for this size; owners of smaller cats need a different SKU
Across the reviewers we read, Advantage II is the default OTC topical recommendation for cats. On r/Pets and r/CatAdvice, owners repeatedly cite vet recommendations for the product, and verified-purchase reviewers at Walmart and Chewy describe fleas dying within hours and scratching stopping within a day. The active ingredient is formulated specifically for felines, which is the central distinction from cross-species dog products that can be toxic to cats.
There is honest disagreement on duration. An r/CatAdvice thread (high-trust community) flagged that for indoor-only cats, doses 'barely seem to last a month' as advertised — a pattern other Pets-subreddit users echoed, attributing it to regional flea resistance rather than product failure. r/Pets users in regions with heavy resistance reported switching to prescription Revolution Plus or Bravecto when Advantage II underperformed, suggesting it works well as a first-line OTC option but isn't a guaranteed fix in resistance hotspots.
The 4-month supply format makes the per-dose cost competitive with prescription alternatives, and reviewers consistently praise the safety profile — particularly the lack of seizure-style reactions reported with budget brands.
- Highlight 1
- Advantage II Large Cat is a leading brand in cat flea treatment and prevention for large cats over 9 lbs., at least 8 weeks of age
- Highlight 2
- Vet-recommended, easy-to-apply monthly topical treatment – no hard-to-swallow pills, no prescription needed
- Highlight 3
- Delivers total flea protection – kills adult fleas, flea larvae and flea eggs through contact
- Highlight 4
- Same-day effectiveness – kills fleas within 12 hours of application and keeps working for 30 days
- Highlight 5
- Fragrance-free formula, waterproof after 24 hours of application
The ingredient selamectin is formulated specifically for cats and dogs. Revolution website published a study in cats, overall very safe. The ...
Both my cats are indoor only, I use Advantage II for their respective sizes but the doses barely seem to last a month like they're supposed to.
Trust tier reflects our editorial assessment of the source, not the individual quote. Hover for the rationale. See how we tier sources →
“Advantage II for Large Cats” · My Honest Review + Tips!
If the consensus convinced you
Check current price on Amazon
Pricing and availability change frequently. Tap through to confirm before buying.