Frontline and Advocate are two of the most well-known flea treatments in the UK, but they work differently and protect against different parasites. Choosing between them depends on what your pet needs protection from and how much you want to spend.

What They Cover

Frontline (fipronil): Kills fleas and ticks. The original Frontline Spot-On does not kill worms. Frontline Plus adds an ingredient (S-methoprene) that also prevents flea eggs from developing. Frontline Spot-On is now available without a prescription.

Advocate (imidacloprid + moxidectin): Kills fleas, prevents lungworm, treats roundworms, hookworms, whipworms, and ear mites. It does NOT kill ticks. Advocate is prescription-only.

Cost Comparison

For a medium-sized dog, typical UK prices per monthly dose:

  • Frontline Spot-On: £4–£6 per pipette (available over the counter at pet shops and supermarkets)
  • Frontline Plus: £6–£8 per pipette
  • Advocate: £8–£15 per pipette from a vet or online pharmacy (prescription required)

Annual costs: Frontline runs £48–£96 per year; Advocate costs £96–£180. However, if you need separate worming treatment alongside Frontline, the combined cost closes the gap.

Effectiveness Against Fleas

There is growing evidence that fleas in many parts of the UK have developed resistance to fipronil (Frontline's active ingredient). A 2023 study published in Parasites & Vectors found reduced efficacy of fipronil against UK flea populations. Many vets no longer recommend Frontline as a first-choice flea treatment for this reason.

Advocate's flea-killing ingredient (imidacloprid) remains effective, and resistance has not been widely documented in the UK. Most vets consider Advocate a more reliable flea treatment than standard Frontline.

Lungworm Protection

Lungworm (Angiostrongylus vasorum) is a potentially fatal parasite spread by slugs and snails. It is now found across the UK, particularly in southern England and Wales. Advocate is one of the few monthly treatments that prevents lungworm. Frontline does not provide lungworm protection.

If you live in a lungworm-risk area, Advocate or an alternative lungworm preventative is strongly recommended.

Prescription Requirements

Frontline Spot-On is available without a prescription from pet shops, supermarkets, and online retailers. This makes it more convenient and often cheaper. Advocate requires a veterinary prescription, which typically costs £10–£20 if you want to buy from an online pharmacy rather than your vet.

Which to Choose

If you just need basic flea protection and your area has no lungworm risk, Frontline Plus is the budget option — though be aware of potential resistance. If you want broader parasite coverage including lungworm, Advocate is worth the higher cost. Many vets now recommend Advocate (or similar prescription products) as the standard of care, particularly for dogs that spend time outdoors.

Use VetCost to compare prescription and medication prices at practices near you. The CMA found that medication mark-ups are one of the biggest sources of price variation between practices.

Last updated: March 2026. Prices based on UK retail and veterinary data. Always consult your vet about the best parasite protection for your pet's lifestyle.