Frontline Plus, 45-88 lb

The verdict

The long-standing over-the-counter spot-on, and the reason it stays relevant is the second active ingredient: fipronil kills adult fleas, and (S)-methoprene targets eggs and larvae, which is the half of the population living in your carpet rather than on your dog. Frontline state it protects for a full month, kills adult fleas, flea eggs, flea larvae, ticks and chewing lice, and is waterproof 24 hours after application. This pack is banded for dogs of 45 to 88 pounds. Owner feedback is genuinely divided on effectiveness, which reflects real regional resistance patterns as much as anything — some areas have flea populations that respond poorly. If it is not working where you live, that is a specific and useful thing to tell your vet rather than a reason to double up.

Drawbacks

• Effectiveness reports vary by region — resistance is real
• Monthly application is easy to forget

Researched from the manufacturer’s listing, its published specifications and what owners report. We do not test products on dogs.

What the listing says

• Targets eggs and larvae as well as adult fleas
• Waterproof 24 hours after application
• Widely available without a prescription

Specifications

Specs come from the manufacturer listing and Amazon’s public product data. A field that reads “Not stated” is one we have not verified — not one the product lacks. We research and analyse; we do not test products on dogs.