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Giardia Dog Poop Pictures and What They Mean

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giardia virus picture
Giardia intestinalis, also known as Giardia lamblia, G. duodenalis, and Lamblia intestinalis, a flagellated parasite that reproduces in the small intestine and causes giardiasis, 3D illustration

Giardia is a single-celled parasite of the intestines. This microscopic organism can infect dogs, people, other mammals, and birds. About 15% of dogs in the United States have Giardia in their gastrointestinal system, so it’s a fairly common disease.

When dogs have a Giardia infection, known as giardiasis, they develop diarrhea because the parasite interferes with the gut’s ability to absorb water and nutrients. Thus, the stool contains extra liquid.

What are the clinical signs of Giardia (Giardiasis) in dogs?

In some dogs, Giardiasis infection is asymptomatic, or subclinical. When your dog shows a clinical Giardia infection, you may notice:

  • Copious watery diarrhea or greasy, fatty stools
  • Passing several stools a day
  • Foul smelling gas
  • Loss of appetite
  • Loss of energy
  • Vomiting
  • Dehydration
  • Weight loss

Color & Appearance of Giardia Poop (With Pictures)

Click on the links in the summary below to view pictures:

Color/appearanceWhat it likely meansWhat you should do
NormalHealthy dog or subclinical GiardiaBring a fecal sample to the vet for testing
Soft, like melted ice creamStress reaction, irritated intestine, or GiardiaContact vet for an exam, bring a fecal sample
Watery, brown or yellowIntestinal parasite, Bacterial or viral infection, Giardiasis Toxic reaction, pancreatitisContact vet immediately
Greasy  Intestinal inflammation, Pancreatitis, poor fat digestion GiardiasisContact vet if the greasy stool persists more than a few days, if you see blood, or if your dog is also vomiting
GreenGiardiasis, Allergic reaction, Eating grass, or Rat poisoningIf you see persistent green stool, or if your dog is also vomiting, contact your vet immediately

What does Giardia poop look like?

Dogs with Giardia can have poop that ranges in appearance. With subclinical infections, the stool may look completely normal. Otherwise, it can be soft like melted ice cream, extremely watery, greasy, or have a greenish color.

Naturally, each poop variation listed above can also occur with other diseases or conditions. So, whenever you have unexplained diarrhea, bring a sample to your vet for diagnostic testing.

Option 1: Giardia Poop Has a brown & normal appearance

Brown, firm poop that looks normal usually means your dog is healthy. However, sometimes a pooch can have normal-looking poop and still have a subclinical infection. If you suspect Giardiasis in your dog, have his feces tested.

normal dog poop

Option 2: Giardia poop has a soft (like melted ice cream) appearance

When your dog’s poop looks like a pile of melted ice cream, it can mean your pup is stressed but otherwise healthy. It can also point to an irritated intestine. A soft stool occurs when the colon isn’t absorbing enough water from undigested food.

Option 3: Giardia poop becomes watery stool

Watery diarrhea in dogs can point to a serious condition. When you see runny poop, it may mean your pup has:

  • An intestinal parasite like roundworms
  • A bacterial infection like Salmonella
  • A viral infection like parvo
  • Pancreatitis
  • A toxic reaction

When your dog has a watery stool, the condition can quickly become life-threatening due to fluid loss. Contact your veterinarian immediately.

Option 4: Giardia poop looks like greasy stool

When your dog’s stool looks greasy, it can mean there’s a problem with the pancreas or with fat digestion. It’s also commonly seen in dogs infected with Giardia.

Option 5: Giardia poop looks green

A green stool can be caused by different things:

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  • Eating too much grass
  • An allergic reaction
  • A Giardia infection
  • Poisoning

If your dog has a green stool and is vomiting, call your veterinarian immediately. He may have eaten some rat bait.

green dog poop on grass

How can I determine if Giardia is present in my dog’s poop?

The only way to confirm Giardia is a fecal test. The appearance alone of your dog’s poop will not give you enough information and confidence that your dog still has giardia. If your pooch has unresolved diarrhea, take him to the vet.

At the exam, your dog’s doctor will get a history of his behavior and symptoms. Depending on the poop and history, he may run other diagnostic tests, including:

  • Parvovirus test
  • Blood test for toxins
  • Fecal exam for parasites

Sometimes, your veterinarian will see Giardia cysts in a routine fecal flotation, but they’re not always present. Repeated tests may be needed for a diagnosis.

If other conditions are ruled out, the clinic may also run a specialized analysis of the poop to detect Giardia-specific proteins from the parasite’s cell wall.

How do dogs get Giardia (Giardiasis)?

Infected people and animals pass Giardia cysts in their feces, and dogs become infected by ingesting the cysts. Your dog can pick up Giardiasis by:

  • Coming in direct contact with infected poop
  • Walking through, rolling, or playing in a contaminated area, then licking his fur or paws
  • Sniffing an infected dog’s hind end and then licking his nose
  • Drinking water that was contaminated by infected poop
  • Killing contaminated rodents or other prey
  • Traveling in a contaminated animal crate


  • Dr. Liz (Elizabeth) Guise graduated from the University of Minnesota with a doctorate in Veterinary Medicine (DVM). She worked as a veterinarian for two years before working for the US Department of Agriculture for 13 years.

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Disclaimer: This website's content is not meant to be a substitute for veterinary care, diagnosis, or treatment. Always consult with your veterinarian to determine the best course of action. Read More.

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