Giardia in Dogs

Giardia Trophozoite.  Courtesy of Dr. Chris Adolph, Southpark Veterinary Hospital

Giardia is a single-celled parasite that lives in your dog’s intestine. It infects older dogs but more frequently infects puppies. Dogs become infected when they swallow Giardia that may be present in water or other substances that have been soiled with feces.

How will Giardia affect my dog?

Many dogs infected with Giardia do not get any disease. Giardiasis, the disease caused by Giardia infection, usually results in diarrhea. Having giardiasis for a long time can cause weight loss; poor condition; and even death.

How do I prevent my dog from getting Giardia?

The best way to prevent Giardia infection is to make sure that your dog has safe, clean drinking water. It is important not to allow dogs to drink water from areas where other animals have left their feces.

Your veterinarian can perform a test on your dog’s feces to see if it has giardiasis. If your dog is infected with Giardia, your veterinarian can prescribe safe, effective treatment for control of the disease.

To prevent spreading Giardia (and other parasites), pick up the feces left by your dog immediately and place it in the trash. Be sure to avoid contact with the feces by using gloves, a bag over your hand, or a scooping device.

Can humans be harmed by Giardia?

Giardia is a common cause of diarrhea in people, but dog Giardia is not generally considered to spread from animals to humans.  While human Giardia may infect dogs and then be passed on to humans, the majority of human cases are of human origin

For veterinary professionals, more detailed information on Giardia can be found at

Did you know?

  • Giardia in dogs can cause diarrhea, vomiting, weight loss, poor condition, or death. However, many infected dogs show no symptoms.
  • People can get giardia, causing diarrhea or other problems, but rarely from dogs.
  • Dogs get giardia from water that has been soiled with feces. Give your dog safe, clean water to drink.
  • Pick up your dog's feces immediately, avoiding contact with your skin.

Ask Your Veterinarian

About Giardia

Diarrhea in dogs, even intermittent, may be caused by giardia. Because giardia can be transmitted to humans, it is important both to keep your environment free of dog feces and to see your veterinarian for testing and safe, effective treatment if you think your dog may be infected.