Worming your Dog

By Dr. Francesca Matthews

When we talk about 'worms' in pets we are not talking about the common garden earth worm, but specialised worms that have developed to thrive in the intestines and other organs of our family pets.

Dogs are affected by a number of worms. They should be regularly treated to ensure freedom from infection and to reduce the potential for causing disease in humans.


Detailed below are the main worm species we want to protect our dogs against, followed by details of a recommended worming programme.





Infestation with roundworms can cause symptoms of lethargy, vomiting, diarrhoea or constipation, poor growth rate, dull coats, a pot belly appearance and coughing.

All puppies are born with roundworms which are passed from their mother during pregnancy.

In order to reduce the number of worms passed on during pregnancy and lactation, the mother should be wormed prior to mating, during pregnancy, and also while nursing the puppies. Puppies should be wormed regularly from 2 weeks of age.

See our section on zoonoses regarding the potential of roundworms being passed on to humans.




These worms can cause severe illness in puppies and dogs. This is because they attach to the walls of the dogs' intestines and feed on their blood. This can cause anaemia, weakness, and even death in severe infections.

The hookworm is passed in the mothers milk to the puppy. The infective stages also live in the ground, and contact with infected ground surfaces also spreads the disease. Picking up faeces promptly, ensuring dogs are housed in raised dog kennels and regular worming is essential to control hookworm.

See our section on zoonoses regarding the potential of hookworms being passed on to humans.




Whipworms are generally found in dogs over 12 weeks of age, and they can cause intermittent bloody diarrhoea and scooting of the dogs anus along the ground due to the adult worms venturing to the surface (the dogs anus) to lay their eggs which causes itching.

The worms are spread by eating infected soil or licking their own or another dog’s contaminated fur or paws.




Tapeworms (including the Hydatids tapeworm) are found when dogs are fed uncooked sheep meat or offal or infested with fleas, which can carry tapeworm larvae. These worms cause little harm to the dog, but they are a serious health risk to humans.

See section on zoonoses regarding the potential of tapeworms being passed on to humans.


Recommended Worming Programmes


Important notes:


  1. You must have an accurate weight for your dog prior to worming to ensure the correct dosage is given. This will give the maximum effect and minimise the risk of the development of worms that are resistant to treatment.
  2. Make sure the wormer being used is effective against the worms it needs to be effective against. Not all animal worm treatments are created equal.
  3. Regular worming should be carried out throughout the entire life of your dog. This is to ensure your dog remains disease free and also to minimise the chances of disease caused by roundworms and hookworms being passed onto humans. .

General Guidelines

Puppies should be wormed every 2 weeks from the ages of 2 - 12 weeks. The wormer must cover both roundworms and hookworms.

From 3 months of age all dogs should be wormed with a good broad spectrum wormer, that does roundworms, hookworms, tapeworms and whipworms every 2 - 6 months (every 3 months is ideal), depending on their level of exposure to these worms. Note that the majority of wormers sold independently of the veterinary clinic do not cover all these worms. Talk to us about the best options for your dog.

Combination flea and worm products


Some of the newer generation flea products on the market claim to provide worming for your dogs as well as flea treatment. This is true in the most part but you must be aware that if you are using one of these products to flea and worm your dog, you should still worm your dog with a worm tablet that contains a tapewormer at least annually, as these combination products do not specifically target tapeworms. Contact us to discuss this further.


Copyright and Disclaimer