Giardia in Dogs

Giardia is a one-celled organism found in the mucosal lining of the small intestine of dogs. This organism affects not only dogs but also people. This page looks at how a dog becomes infected with giardia, the symptoms of infection, diagnosis, conventional treatment, as well as effective natural remedies to treat canine giardia.

Giardia in Dogs Giardiasis is an extremely common infection caused by the intestinal protozoa giardia that affects the digestive system of humans and many animals including dogs and cats worldwide.

Dogs become infected by ingesting the giardia cysts.

How can dogs come in contact with the cysts?

One way is from the environment. For example, if a dog drinks contaminated water with infected animal feces in which the cyst form of giardia resides, the dog will become infected.

Sources of contaminated water include ponds, streams, puddles, etc. Giardia cysts may also exist in soil and grass where an infected animal has gone to the bathroom. Giardia cysts are extremely hardy - they can survive for weeks in the environment provided that it is damp and not too hot.

A dog can also swallow or ingest giaria cysts by coming into contact with another dog that is infected with giardia.

Once a giardia cyst is ingested by a dog, it makes its way to the dog's small intestine, where it opens up and releases the active form of the parasite which attaches itself to the intestinal wall and begins to reproduce by cell division. Then it will encyst itself once again and is passed outside via the dog's feces.

People can be infected by Giardia as well. Animals tend to be more resistant to it than humans are. But if an aminal does not have a strong immune system, it cannot fight off the infection and will fall victim to the parasites as well.

As in all cases of infections, the severity of the illness depends on the overall health of the host.

In North America, infection of Giardia in dogs has been reported at about 8%, with much higher levels in puppies (36% to 50%). Animals in shelters and kennels run a much higher risk of Giardiasis - up to 100%.

Symptoms of Giardia Infection

Dogs with Giardia infestations sometimes show no symptoms at all. If they do, symptoms usually show up after 7-10 days of ingestion.

Dogs who are more likely to show signs and symptoms are puppies, old dogs, those who have other intestinal parasites such as worms, and those who have compromised immune systems.

Symptoms of giardia are varied but, generally speaking, the symptoms are most commonly associated with digestive disorders, such as:

  • acute or chronic diarrhea;
  • nausea and vomiting;
  • dehydration;
  • weight loss;
  • abnormal stools (pale, greasy-looking, covered in mucus, bloody, bad odor).

Dogs with giardia may have acute diarrhea for several days, which in serious cases, can cause dehydration. On the other hand, the diarrhea may wax and wane and become a chronic issue, making it all the more difficult to deal with and diagnose.

Diagnosis of Giardia in Dogs

The traditional way to diagnose Giardia in dogs has been by microscopic identification of the cysts in feces of affected dogs. However, the cysts are small and delicate and are not passed with every stool, making diagnosis very difficult.

Recently, the first commercially available diagnostic test using ELISA technology designed specifically for dogs and cats has been released. The test uses just a small sample of feces and can be completed in a very short time (8 minutes), and the cost is low.

Conventional Treatment for Giardia in Dogs

Conventionally, giardia infections are treated using medications, which include Metronidazole (Flagyl), Fenbendazole, Albendazole, and Quanacrine.

Metronidazole is most commonly prescribed but is only about 67% effective in dogs and can be toxic to the liver. It is also suspected to be teratogenic (it can cause physical defects in embryos) and therefore should not be used on pregnant animals.

Fenbendazole seems to have fewer side effects than metronidazole. However, there have been cases in which dogs infected with Giardia have failed to respond to treatment with both metronidazole and fenbendazole.

Albendazole has been shown to be effective in the treatment of Giardia but has been associated with bone marrow toxicosis.

Quanacrine is effective in dogs; however, the drug can cause anorexia, lethargy, and fever.

Natural Remedies for Dogs with Giardia

Natural Remedies for Giardia in Dogs As conventional medications have so many side-effects, it is much better to seek natural alternative remedies. Fortunately, there are quite a few remedies that can be used to treat this infection.

Grapefruit Seed Extract (GSE)

GSE is perhaps the most effective natural remedy that can be used to treat Giardia in dogs.

You can use one capsule (10-15 drops of the liquid) of GSE per 10 pounds of body weight, up to 3-5 times a day, for up to 14 days. Mix the drops with food, water or a bit of veggie broth.


Herbs that contain the active alkaloid constituent berberine, such as Goldenseal and Oregon grape, are effective in treating Giardia infections in dogs.

Berberine acts like an antibiotic, and since it is water soluble and alkaloid, it can withstand the digestive acids that destroy many other types of antibiotics in the digestive tract.

Tinctures of goldenseal or Oregon grape can be given to a dog infected with Giardia twice a day for up to 10 days.

Other herbs that are useful include garlic, licorice and cleavers.

For diarrhea caused by Giardia, the herb slippery elm is effective.

Other Supplements

Other natural supplements that should be given to a dog with giardia are:

  • Probiotics - to restore the balance of microflora in the dog's intestinal tract.
  • Digestive Enzymes - to aid proper digestion and absorption of nutrients.
  • L-Glutamine - to help protect the stomach and intestinal lining and also may prevent the formation of stomach ulcers.


An Excellent Natural Remedy for Giardia in Dogs

This formula contains the herbs licorice, slippery elm, and alfalfa, as well as supplements such as digestive enzymes, probiotics, L-Glutamine, and more. It gives advanced gastrointestinal support to dogs suffering from digestive problems caused by Giardia, inflammatory bowel disease, food allergies, and so on.

If your dog is infected by Giardia, use this product in conjunction with GSE for best result.