Intestinal Worms In Dogs: Preventing & Treatment

Worms are a parasite that can live in the internal organs of animals. All dogs have probably had them or will get them at some point in their lives, so will need treatment or prevention.

If worms are left untreated, they can cause damage to internal organs and eventually a loss of life. The longer they are in there and the longer they are left to grow, the more chance they have of being passed on to other animals and even humans.

The best way to prevent them in the first place is to give your dog a regular worming tablet or liquid. Most should be given every three months or so.

Even if you do give your dog regular wormer, it is still good to know what to look out for and how to cure worms if it happens.

How can I tell if my dog has worms?

The symptoms of worms can vary depending on your dog. Some may not show signs at all, depending on the worm they have. Some symptoms can also be signs of other things.

But as standard, you should look out for:

  • Diarrhoea or vomiting
  • Extreme coughing
  • Lethargy or unusual tiredness
  • Weight loss
  • Bloating (most common in puppies)
  • Dull coat
  • Scooting along the floor
  • Visible worms in faeces or around their bottom

Types of worm in dogs

One thing which makes the treatment and prevention of worms hard in dogs is that there are various types, which all require different medications and show various signs depending on where they are living.

There are six types of worms that can affect dogs:

  • roundworms
  • tapeworms
  • lungworms
  • hookworms
  • whipworms
  • heartworms

Not all worms are here in the UK, but it is good to know what to look out for anyway. Some are in Europe, so you need to be aware if you take your dog abroad.


These are the most common worms dog owners will experience in the UK.

There are two types; Toxocara canis (T. canis) and Toxascaris leonina. The former is most common in puppies and human transmission.

Newborn puppies are commonly infected with this from birth through their mother’s milk, so it is vital they receive the proper treatment. Adult dogs can also get it through contaminated soil or eating rodents.

They usually start out in the intestinal tract but then work their way into other organs. They’re treated with simple worming medication and should be prevented by most tablets on the market too.


Tapeworms are usually transmitted to dogs via fleas. Immature fleas (larvae) ingest worm eggs, and if your dog then grooms itself and swallows an infected flea, they can develop tapeworms.

This is why it is vital to treat your dog for fleas as well as worms

They can also get it from infected carcasses (such as rodents, sheep, or rabbits).


This worm is slightly different from the others, living in the dog’s blood vessels.

If your dog eats a slug, snail or frog, the parasites within an infected animal can grow and develop into lungworms in your dog. Gastropods often feed on dog faeces, and if this has been infected with worms, the cycle continues.

This is the worm that often gives the dog respiratory symptoms, such as loss of breath or wheezing. If left untreated, it can cause haemorrhages in the lungs, or just about any other organ. The danger from eating slugs is why you should always be careful if your dog eats grass.


Dirofilaria immitis is not seen in the UK. It is passed on through mosquitos which are rare here but can be an issue if you are travelling abroad.


Not very common in the UK but still seen in Europe, so worth being aware of. Hookworm is a blood-sucking parasite with teeth. Because of how many nutrients they take from dogs, they can cause fatalities, especially in puppies.

The scary thing is that hookworm larvae can get through the canine’s skin, so they don’t even need to have eaten anything to get it.


Also more common abroad than here in the UK. Whipworms don’t often show any symptoms until the severe stages, where diarrhoea will be bloody.

It is often passed on through eating contaminated soil, or contact with infected faeces.

What causes worms in dogs?

How a dog is infected with worms can depend on the form of the worm. It can be anything like:

  • Passed on via infection from mother
  • Swallowing worm larvae with mother’s milk
  • Catching or eating dead animals (especially rodents or rabbits)
  • Swallowing fleas during grooming (tapeworm)
  • Picking up worms faeces or soil whilst outside
  • Contact with or swallowing slugs or snails (lungworm)

Most puppies are actually born with worms! So, it is a natural event, but it is up to you to stop their spread and damage as they get older.

Puppies and Worms

Diagnosing worms in dogs

A vet will fully examine your dog and ask some questions about its symptoms and lifestyle.

They will often need a stool sample, and this should be done annually anyway to ensure there is nothing there which is underlying with no symptoms.

A lot of animal hospitals and private, specialist animal stool sample businesses will inspect faecal matter as and when you suspect an issue, or just as a precaution. You may wish to do this every three months at the time of worming, to ensure your chosen product is working well.

What to do if you suspect your dog has worms

If you suspect your dog already has worms, always go to your vet for advice for the first port of call as opposed to buying and starting home worming treatment.

They will be able to recommend the best course of action, which could involve stronger medication than is available to buy online or without a prescription. You may not feel confident administering it yourself, so they can use injections or arrange regular visits.

Some worming treatment isn’t suitable for certain breeds, so they can choose a medication based on your dog and the severity of the issue.

They will also be able to check that these symptoms aren’t due to any other medical issue, such as allergies, respiratory problems or digestive trouble.

Worming pregnant dogs

You should aim to worm bitches before mating, so the worming treatment can get to work. Then again after the first 45 days of pregnancy before a final dose after giving birth.

They should then be wormed alongside their pups at 2, 5 and 8 weeks and after weaning. A bitch should also be treated for fleas before mating.

Before mating, a strong wormer like Drontal Plus is recommended. During pregnancy, something like Panacur Suspension is ideal. This is given orally (or in food), once a day, from day 40 of the pregnancy until 2 days after giving birth. Repeat the Panacur treatment post whelping too.

Regular tablets are not easy to give due to the fact you shouldn’t keep approaching an expectant dog, so an oral suspension which is appealing yet they don’t really think twice about taking is good.

We have recommended the best worming treatment for expectant dogs on our Dog Wormers review page.

Tapeworm and travel

A vet must officially treat your dog for tapeworm and record it in their pet passport or third-country official veterinary certificate every time you want to bring it into the UK.

Any over-the-counter, at-home medication will not be sufficient, as your vet needs to record the name and manufacturer of the product, the date and time they treated your dog and their stamp and signature within the passport.

The country exceptions are if you are coming from Finland, Ireland, Malta or Norway

It should be done no less than 24 hours and no more than 120 hours before you enter the UK. Without this, your pet will likely be put into quarantine. The treatment needs to be approved in the UK and must contain praziquantel or an equivalent proven to be effective against the Echinococcus multilocularis tapeworm.

If you’re leaving the UK for a holiday or short trip, your dog must be treated by a vet before you go. You must wait 24 hours before re-entering the UK and return within 5 days for this treatment to still be accepted, or you’ll need to get another treatment abroad. Dogs should be given another treatment within 28 days of returning to the UK.

Even though tapeworm is the big issue here, it is still a good idea to protect your dog against all forms of worm before you go. The same applies to if you are coming or going from one of the above-listed countries.

If you’re confused, ask your vet in plenty of time.


How are worms passed on to other animals?

As you have read above, it is common for puppies to become infected through their mother’s milk or the close contact they have with their mother as their immune system builds up.

Other animals can also become infected through the dog’s faecal matter and contaminated soil, which is why it is vital to clean up after your dog ASAP and ensure your dog avoids the dog poo left in public places by irresponsible owners.

Human infection is rare but good hygiene needs to be followed just in case. Wash hands after playing with your pet, don’t let them lick your face and be careful when clearing up after them.

What do dog worms look like?

Tapeworms are like flattened grains of rice joined together. This is most commonly seen in their faeces or around their bottom. Small parts of the worm can also break off and be seen on other parts of the dog’s body.

Roundworms look more like spaghetti with tapered ends. They can be found in faeces but is mostly seen in puppy sick, and they will often be curled around.

You can Google images for both if you like – but you probably won’t appreciate the results!

Are natural worming products any good?

We would always say to go with the vet-approved medication over any herbal or natural products when it comes to health issues such as worms, fleas, ticks and other potentially serious problems.

Most natural medication will be daily, in the form of a treat or drop which goes into the food. They also usually prevent any intestinal and digestive issues as opposed to particularly protecting against worms.

If you do choose this course of action, give your dog regular stool samples, talk to a qualified natural vet and also inform your regular vet to ensure it doesn’t interfere with other medication or food.