Unbranded, secure packaging guaranteed
When you sign up
Genuine pet medicine
Stronghold for dogs is a monthly prescription flea treatment containing selamectin. It kills adult fleas, flea eggs and larvae, and prevents new infestations for a month. Part of the Stronghold range from Zoetis.
Topical spot-onPOM-V itemOne pipette, once a month
AgeSuitable for dogs from 6 weeks old
StrengthsSix strengths, 15mg for puppies to 360mg for dogs up to 60kg
BreedingCan be used in pregnant, lactating and breeding dogs
Jump to product details ↓Treating a cat? See Stronghold for cats →
This item requires a current prescription from your vet before we can dispatch it. The good news? Sorting it out is simple and only takes a moment.
As soon as your prescription reaches us, our team will verify the details and get your pet’s treatment posted out to you.
Stronghold for dogs is a monthly prescription flea treatment containing selamectin. It kills adult fleas, flea eggs and larvae, and prevents new infestations for a month. Part of the Stronghold range from Zoetis.
Topical spot-onPOM-V itemOne pipette, once a month
AgeSuitable for dogs from 6 weeks old
StrengthsSix strengths, 15mg for puppies to 360mg for dogs up to 60kg
BreedingCan be used in pregnant, lactating and breeding dogs
Jump to product details ↓Treating a cat? See Stronghold for cats →
We can only dispatch this medicine once we’ve received and approved a valid veterinary prescription.
Stronghold spot-on for dogs is a prescription-only (POM-V) treatment made by Zoetis. Its active ingredient, selamectin, is absorbed through the skin and spreads through the body. It disrupts parasites’ nerve signals, which paralyses or kills them.
Stronghold doesn’t cover ticks, tapeworms, hookworms or lungworm in dogs. Your vet may add a separate treatment for these from our flea, tick and wormer range.
Same maker, same selamectin base. Stronghold Plus for cats adds sarolaner, which brings ticks onto the licence, but it’s for cats only. There’s no Stronghold Plus for dogs.
| Stronghold | Stronghold Plus | |
|---|---|---|
| Active ingredients | Selamectin | Selamectin + sarolaner |
| Species | Cats and dogs | Cats only |
| Ticks on the licence | No | Yes |
| Legal category | POM-V | POM-V |
For cat strengths and the full range, see our Stronghold spot-on page.
Legal category: POM-V
View the Summary of Product Characteristics (SPC) information for this product
Apply one pipette to the skin at the base of your dog’s neck, in front of the shoulder blades, once a month or as your vet directs. Use the strength that matches your dog’s current weight, and follow the label and your prescription.
Hold the pipette upright and press the cap down to break the seal. Part the fur until you can see skin, then squeeze the whole pipette onto one spot. Don’t rub it in. Don’t apply to a wet coat, and for ear mites, don’t put it into the ear canal. Your dog can be bathed from 2 hours after treatment.
For more on keeping fleas out of your home, read our flea and tick guides.
Stronghold for dogs is available in packs of 3, 6 or 15 pipettes, depending on the strength.
| Strength | Cap colour | Dog weight | Pack sizes |
|---|---|---|---|
| Stronghold 15mg for puppies (0.25 ml) | Rose | Up to 2.5 kg | 3 or 15 pipettes |
| Stronghold 30mg for toy dogs (0.25 ml) | Violet | 2.6 to 5 kg | 3 or 6 pipettes |
| Stronghold 60mg for small dogs (0.5 ml) | Brown | 5.1 to 10 kg | 3 or 6 pipettes |
| Stronghold 120mg for medium dogs (1 ml) | Red | 10.1 to 20 kg | 3 or 6 pipettes |
| Stronghold 240mg for large dogs (2 ml) | Green | 20.1 to 40 kg | 3 or 6 pipettes |
| Stronghold 360mg for extra-large dogs (3 ml) | Plum | 40.1 to 60 kg | 3 pipettes |
Dogs over 60 kg need a combination of pipettes, prescribed by your vet.
Select the treatment you would like to order
Provide all the information about your pet
Your order will be sent in discreet packaging.
Yes. POM-V items require a valid prescription from your UK vet.
Upload your prescription during checkout.
Photos must be clear. If details are wrong or expired, orders can’t be processed. This is standard across UK pet pharmacies.
No. Under UK law, vets must provide a written prescription if you request one for a POM-V medicine. They may charge a reasonable fee for issuing it, but they cannot refuse. This allows you to choose where to buy your pet’s medication, whether directly from your vet or from a registered UK pharmacy such as Ashcroft 4 Pets.
In the UK, most POM-V prescriptions are valid for 6 months, unless your vet specifies a shorter duration. Prescriptions for Schedule 2 or 3 controlled medicines are usually valid for 28 days and are not repeatable. At Ashcroft 4 Pets, we follow these same UK veterinary guidelines to ensure your pet’s medication is dispensed safely and legally.
At Ashcroft 4 Pets, we are a fully VMD-registered and accredited online retailer. This means every prescription and over-the-counter pet medicine we supply is safe, genuine, and dispensed according to UK law.
We follow all Veterinary Medicines Directorate (VMD) rules, and our team checks every prescription carefully before processing. You can order with confidence, knowing your pet’s health is in the hands of experts and all medicines are traceable, legally supplied, and authentic.
In the UK, most repeat prescriptions for POM-V medicines are valid for up to 6 months from the date your vet issues them. You can order multiple times within this period if your vet has authorised repeats.
For controlled medicines (Schedule 2 or 3), the prescription is valid for 28 days only and cannot be repeated. These medicines are strictly regulated due to their potential for misuse.
At Ashcroft 4 Pets, we follow UK law carefully, ensuring all prescriptions are dispensed safely, legally, and in the exact amounts prescribed.
If your vet prescribes a human medicine for your pet under the Cascade, we can usually dispense against that prescription (with the right checks).
Many pet owners wonder if the tiny pests bothering their dog or cat can make the jump to them. The short answer is yes, fleas from your pet will happily bite a human, but they can’t actually live on you.
Not every flea treatment suits every dog. Compare formats, lifestyle fit, and what’s actually licensed for general sale vs prescription-only in the UK.
Most UK adult dogs need worming every three months — monthly if they scavenge, hunt or eat raw food. Vet-reviewed schedule by age and lifestyle.
