A guide to worming your dog

What are worms in dogs?

Worms are intestinal parasites that live inside your dog’s digestive system or, in some cases, other organs such as the lungs. All dogs are at risk, whether they’re mostly indoor or outdoor pets.

There are several types of worms a dog might get:

• Roundworms

Roundworms are the most common type of worms in dogs. There are mainly two types: Toxocara canis and Toxascaris leonina. They look like long, white spaghetti and live in the intestines. Puppies can be especially vulnerable as roundworms can be passed from their mother during pregnancy or through her milk.

• Tapeworms

Tapeworms in dogs are flat, segmented worms that can grow quite long if they’re left untreated (up to a foot or two!). The most common type, known as Dipylidium caninum, is spread by fleas. The individual tapeworm segments often look a bit like like grains of rice in your dog’s faeces or around their anus. Tapeworm treatment for dogs is an essential part of routine worming.

• Lungworm

Lungworm (Angiostrongylus vasorum) is less well-known but can be particularly nasty if left untreated, causing severe illness or even death. Dogs typically become infected by eating slugs or snails carrying the larvae, or from contact with their slime trails.

• Hookworms and whipworms

Hookworms in dogs are small but can cause serious health problems such as anaemia, especially in puppies. Whipworms are less common in the UK, but can lead to severe diarrhoea and weight loss.

Symptoms of worms in dogs

The signs of worms in dogs can vary depending on the type of parasite and how severe the infection is. Some common symptoms include:

• Worms in your dog’s poo (can be just the segments).
• Weight loss despite a normal appetite.
• A dull coat or poor condition.
• Diarrhoea, sometimes with blood.
• Vomiting, which may contain worms.
• Dragging their bottom along the floor (scooting).
• A bloated stomach, especially in puppies.
• Coughing (a possible sign of lungworm).

Severe infestations can lead to weakness, anaemia, and in the case of lungworm, potentially fatal bleeding disorders.

How can dogs get worms?

There’s a number of ways that dogs can pick up worms, depending on things like their age and lifestyle.

Puppies

Puppies can be especially at risk of worms because roundworm larvae can pass from their mother through the placenta before birth or via her milk once they’re born. This is why regular puppy flea and worm treatment is essential from an early age.

Adult dogs

Adult dogs can become infected by worms in several ways, including:

• Eating infected prey such as rodents or birds.
• Swallowing fleas carrying tapeworm eggs.
• Swallowing soil, faeces, or contaminated food.
• Accidentally eating snails or slugs (a risk for lungworm).

How to prevent worms in dogs

Preventing worms is generally better than treating them once they’ve become infected. Routine worming with effective worm medicine for dogs as recommended by your vet is generally the best protection.

Other preventative worming measures might include:

• Flea control - since tapeworms are linked to fleas, consistent flea treatment is important.
• Hygiene – make sure you promptly clean up dog faeces from your garden and when out on walks to reduce the risk of reinfection.
• Monitoring puppies - young dogs need more frequent worming than adults.
• Avoiding slugs and snails – reducing exposure can help prevent lungworm.

How often to worm puppies?

To find out the right worming schedule for your puppy, it’s best to speak to your vet. Always use worming products designed for dogs and follow your vet’s instructions.

As a rough guide, worming might begin when they’re two weeks old and continue every two weeks until twelve weeks. After that, monthly worming may be recommended until your puppy is six weeks old. 

What to expect after routine worming

Most of the time, you probably won’t notice any visible changes after giving your dog worming tablets. Modern worm medicines kill worms efficiently. Occasionally, you may see dead worms or segments in their stool for a few days, but often you won’t see anything at all. Side effects are rare, but some dogs can experience mild digestive upset.

How to treat worms once your dog is infected

What to do I do if my dog has worms?

Knowing how to treat worms in dogs quickly can prevent more serious health problems. If you notice symptoms of worms in your dog, such as worms in their poo, weight loss, or coughing, contact your vet for advice. Any suspected lungworm infection, or severe diarrhoea, unexplained weight loss, or visible worms should be checked by a vet immediately.

As for treatment, your vet will recommend the most effective worm medicine for your dog. This might include tablets, spot-on treatments, or injections. Prescription treatments are usually more reliable than over-the-counter alternatives.

What happens if worms aren’t treated?

Untreated worms in dogs can cause a number of issues, including malnutrition and weight loss, intestinal blockages, anaemia (from hookworms), coughing, breathing difficulties, or fatal bleeding (lungworm). In some cases, more severe illnesses or even death, especially in puppies, is possible if worms aren’t dealt with. This is why preventative routine worming and/or seeking treatment if your dog has worms is so important.

Natural treatments for worms in dogs

Some owners look for a natural dewormer for dogs, such as pumpkin seeds or herbal remedies. These may sound appealing, but there’s not much solid evidence to show they’re an effective alternative. Vet-approved worming treatments are a safer and more reliable way to keep your dog healthy. If you want to ask about natural options, you can always consult your vet for advice.

Overall, worms in dogs are common but preventable and generally treatable. With regular deworming, flea control, and good hygiene, most dogs remain free from serious problems.

For more information on spotting potential health problems, see our guide on common dog health issues.