Dogs Worming

Worming Schedule

Does my dogs have worms?

Your dog may have worms even if you have not seen any.

Dogs do not often pass worms in their faeces unless they have a very heavy worm burden and many dogs carrying worms show no outward signs

Signs of a severe worm problem vary but can include vomiting, diarrhoea, pot-bellied appearance, dehydration, weight loss and loss of condition. Sometimes lung damage can cause breathing problems.

Some worm infections can be confirmed by demonstrating worm eggs in the faeces.

Puppies 2 – 8 weeks of age Every 2 weeks
Weaned puppies 3 – 6 months of age Monthly
Adult dogs Every 1 -3 months depending upon risk factors (ideally monthly)
Pregnant bitches Must be wormed during pregnancy. Ask your vet for advice
Please note: Dogs that are regularly in contact with children or slugs and snails may require special programmes. Please discuss this with your vet or nurse

How do I protect my dog from these worms?

While most worming products will kill adult worms, the better wormers will kill developing worms (larvae) as well, which leads to more effective control. No wormers have residual action and if your dog swallows worm eggs or larvae the day after being wormed the larvae will develop into egg-laying adults within one month.

We recommend worming your dog regularly according to the table above.

What worms can affect my dog in the UK?

Roundworms, tapeworms, whipworms, lungworms and hookworms.

Roundworms (or ascarids)

These are the most common worms found in dogs. They resemble spaghetti and are 2-3mm thick and up to 2cm long. Almost all puppies are infected in the uterus or become infected immediately after birth through their mother’s milk. Roundworms are also passed from dog to dog via eggs and larvae in their faeces. The dog picks them up on its coat, paws and muzzle and then ingests them while grooming. These worms can cause poor growth, weight loss, diarrhoea and vomiting.

There are two main roundworms that occur in dogs in the UK. These are Toxocara canis and Toxascaris leonine. They can pose a risk to humans as accidental ingestion of eggs/larvae can result in the roundworm travelling around your body. This is known as visceral larva migrans and if the larvae settle in the eye they may cause blindness. If your dog has contact with children they should be wormed monthly because of this.

Tapeworms (or cestodes)

These are flat and can measure from a few millimetres (Echinoccus) up to 2.5 metres (Taenia hydatigena) in length. They live in the small intestines of dogs and severe infestations may cause intestinal damage due to the physical presence of the worms. Tapeworms are not spread directly from dog to dog. They require an intermediate host.


These are parasites of the large intestine of the dogs. They are thin and 5-7cm long. Dogs can become infected by ingesting eggs in contaminated soil. The eggs are extremely resistant making environmental control difficult. Whipworms can cause bloody diarrhoea, weight loss, anaemia and dehydration especially in a heavy infestation. Eggs are not shed regularly making diagnosis difficult and several stool samples may be required.


These are parasites of the small intestine. Dogs can be infected by ingesting hookworm larvae from contaminated soil or from larvae actively boring through the dog’s skin. Puppies can be infected immediately after birth through their mother’s milk. Larvae boring through the skin may cause an itchy inflammation. Migration through the lungs may cause inflammation and cough. 500 worms can cause a 2kg puppy to lose half its total blood volume in one day leading to death.


These worms can be caught when dogs eat snails or slugs. The adult worms live in the blood vessels of the lungs of the dog and infestation can cause bleeding disorders, neurological signs, coughing and even death. A special worming regime is required if your dog is at risk of lungworm so please speak to your vet or nurse if you are concerned.