Giardia
Common Canine Intestinal Parasite


Giardia is a parasitic protozoan. It is a waterborne protozoa, not a worm.

Protozoa? What is that? Protozoa are single celled organisms. These parasites are commonly found in the intestines of many animals, including dogs. They are flagellates. Flagellates have hair like tendrils hanging down that act as legs to help them move and ' swim '.


Giardia tests rarely find this parasite.

It is very difficult to detect in stool samples.



These microscopic parasites cling to the surface of the intestine, or they can also float free in the mucous lining of the intestine. These parasites can cause inflammation in the intestine. This inflammation can cause extreme digestive upset and diarrhea that can result in severe nutrient loss.

I would be a rich woman if I had a dollar for every person who has contacted me to say that their dog has recurring diarrhea. Next to skin problems, diarrhea in dogs is the most common complaint. Humans can be infected by giardia too. So make sure you wash your hands.

If a dog does not have a strong immune system, it will be unable to resist the infection. The severity of the infection depends on the overall health of the dog. In North America, infection in dogs is reported to be about 8%. The rate of infection in puppies is much higher at about 36% to 50%. Dogs in shelters and kennels are very much at risk... up to 100%.

These Intestinal Parasites
Have Two Stages of Development


  1.  a feeding stage that lives and moves in the intestines.
  2. a cyst stage that leaves the body with the feces

Your dog becomes infected by ingesting ( eating or drinking ) the cysts. The most common ways are:

  • eating the poop of another infected animal or something else that is contaminated with the cysts.
  • drinking contaminated outdoor water from ponds, birdbaths, puddles etc. If you have a well, get it tested.

Once your dog has ingested the cysts, they now have the opportunity to travel through the digestive system and break open in the intestines. There they feed and multiply. Those little things that look like eyes, are actually nuclei. The Giardia protozoa multiplies by dividing in two, thus the two nuclei.

Brilliant eh ?!

Giardia Symptoms



  • - recurring diarrhea, mild to severe
  • - explosive diarrhea
  • - soft, light colored, greasy looking stools
  • - gassy
  • - weight loss
  • - loss of appetite
  • - eating, but still losing weight.
  • - dehydration
  • -listlessness and fatigue
  • mucous in the stool
  • nausea and vomiting
  • excessive grass eating

Some experts see excessive grass eating as a symptom, because eating grass will make a dog purge, either by vomiting or by prompting stool elimination.

Some experts point to stool eating ( copraphagia ) as a symptom, because the infected dog will attempt to regain nutrients and bacteria lost through diarrhea.

Diagnosing Giardia

  1. Take your dog to the vet.
  2. Stage 1 or 2 must be found in the feces.
  3. Three ( 3 ) stool samples should be taken over a period of ten days to two weeks. The reason for this, is that the cysts are passed periodically, not with every bowel movement.

Just because you receive a negative result, does not rule out that your dog may have this parasitic infection. Trust me, I know about this!

My dog Jack, whom you have met on other pages, actually had Giardia for a number of years, if you can believe that! He would show symptoms off and on over this time, but we were never able to pinpoint the problem. He couldn't gain weight, he would have runny, loose, smelly, mucousy,  sometimes bloody diarrhea, uncontrollable bowel movements with occasional vomiting. This went on for years. You can imagine how much I worried about him, but no positive results for giardia were found until many years later.

Giardia Treatment

The most commonly used drug is Metronidazole ( Flagyl ) which is an anti biotic/anti protozoal. This drug can be used alone, or in combination with another similar drug called Fenbendazole.

Neither of these drugs is 100% effective, and each has the potential to cause liver damage. There are other drugs, such as Panacur that are used for this problem too, but none are very effective, and some do have dangerous and unpleasant side effects.

Since conventional medications have so many potential side effects, and are not really that effective for this problem, natural remedies are a good alternative. Here is what I used for Jack. He is infection free now. I give him this program about once a year, just to make sure, because I know that Giardia can reappear.

  • Liquid Silver Shield - #4280-5 - a powerful natural anti-pathogen
  • Probiotic 11 - #1510-1 - eleven different strains of beneficial bacteria to repopulate the gut and make his immune system strong. My dogs get this once or twice a week all the time
  •   Liver Cleanse - #1010-3 - this common garden weed has a long history of use as a liver and kidney remedy. It is high in potassium, a mineral that is easily lost with diarrhea.
  • Black Walnut - #90-8 - natural anti-parasitic used internally to help get rid of many kinds of worms, amoebas, protozoa and fungus
  • Intestinal Soothe and Build -#1106-2 - herbal formula to help ease, soothe and cleanse a toxic bowel. May also help with bloating pressure in the intestinal tract. Note: This product is called UC3-J # 1105-8 in Canada

If your dog will is very sick and will not take capsules in the food you can use Black Walnut Extract - #1755-7 instead. Dosage is three drops per 25 lbs of body weight. Since Giardia can cause severe intestinal inflammation, I like Aloe Vera Juice - #1680-4 to soothe the entire digestive tract.

If your dog is so sick that he will not eat, and has diarrhea if he even looks at food, you can put all of these liquids together and syringe them down the dogs' throat.

A syringe can be gotten at any pharmacy. Sometimes this is necessary.

I would be happy to coach you through this process if you are experiencing these symptoms with your dog.



For more help you can contact me here.

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