Giardia in Dogs: What It Is, How It Spreads, and What to Feed a Dog Recovering From It
At a glance
- Giardia is a single-celled intestinal parasite — not a worm or a bacterium
- It spreads through contaminated water, soil, or contact with infected faeces
- Symptoms include watery or greasy diarrhoea, weight loss, and lethargy
- Treatment requires antiparasitic medication from a vet — diet alone will not clear the infection
- A bland, highly digestible diet supports gut repair during and after treatment
What is giardia and how does a dog get it?
Giardia is a microscopic, single-celled parasite that lives in the small intestine. It attaches to the gut lining, interferes with nutrient absorption, and triggers the watery or greasy diarrhoea that most owners notice first. It is one of the most common intestinal parasites in dogs worldwide, with studies estimating prevalence rates of up to 15% in domestic dogs in developed countries.
Dogs pick it up by swallowing giardia cysts — the hardy, dormant form of the parasite. This happens through drinking from contaminated puddles, streams, or standing water, sniffing or licking infected faeces, or contact with contaminated soil in parks and dog-walking areas. Puppies and dogs with weaker immune systems are at higher risk of developing symptoms.
Once swallowed, the cysts activate in the small intestine, multiply rapidly, and begin disrupting the normal absorption of water, fat, and nutrients. That is why stools often appear pale, greasy, or foamy rather than simply loose. Understanding how giardia damages the gut helps explain why diet matters so much during recovery. Giardia sits within the wider picture of conditions that affect digestive health — a topic covered in depth in the guide to how diet and common health conditions are connected.
What are the symptoms of giardia in dogs?
The most common symptom is intermittent diarrhoea that tends to be soft, pale, greasy, or foul-smelling. Some dogs show symptoms that come and go over weeks. Others remain completely asymptomatic but can still pass cysts and infect other animals.
Symptoms to watch for include:
- Watery, greasy, or foamy diarrhoea — sometimes with mucus
- Weight loss despite a normal appetite
- Bloating or a gassy, uncomfortable abdomen
- Lethargy or reduced energy
- Vomiting (less common but possible)
Symptoms can look very similar to other gut issues, including dietary intolerance or bacterial infection. A vet diagnoses giardia by testing a fresh stool sample for cysts or antigens. If your dog has had loose stools for more than 48 hours, is losing weight, or seems unwell, see a vet rather than waiting it out.
How is giardia in dogs treated?
Giardia is treated with antiparasitic medication — most commonly fenbendazole or metronidazole, prescribed by a vet. Fenbendazole is typically given daily for five days. Metronidazole is often used alongside it in stubborn cases. Neither drug is available over the counter, and neither should be used without a diagnosis.
Alongside medication, hygiene management is essential. Giardia cysts are shed in stools and survive in the environment for weeks. Bathing the dog, disinfecting their bedding, and cleaning any areas they use regularly all reduce the risk of reinfection. This is especially important in multi-dog households.
Reinfection is the most common reason treatment appears to fail. If symptoms return shortly after a course of medication, tell your vet — a second round of treatment or a different drug combination is sometimes needed.
What should you feed a dog recovering from giardia?
During and after a giardia infection, the gut lining is inflamed and its ability to absorb nutrients is reduced. The goal of a recovery diet is to give the gut as little work to do as possible while it heals.
The core principles are straightforward. Feed small, frequent meals rather than one or two large portions. Choose foods that are easy to digest — lean protein, simple carbohydrates, and minimal fat. Avoid anything rich, fatty, or highly processed, as these place extra demand on a gut that is already struggling.
Gentle, freshly prepared food with a short, recognisable ingredient list is well suited to this stage of recovery. Marleybones meals are slow-cooked in-pack from real, whole ingredients with no fillers or artificial preservatives. The recipes are vet-developed and FEDIAF compliant, and the clean ingredient profile makes them a practical choice when a dog's gut needs to be treated carefully. For dogs managing diarrhoea during or after a giardia infection, the same dietary principles apply: simplicity, digestibility, and consistency.
Prebiotic fibre also plays a role in gut recovery. Chicory root, included in Marleybones recipes, contains inulin, a prebiotic that feeds beneficial gut bacteria and helps restore the balance disrupted by giardia. Rebuilding the gut microbiome after a parasitic infection supports a faster, more complete recovery.
| Food type | Suitable during recovery? | Why |
|---|---|---|
| Lean chicken or turkey (plain) | Yes | Easy to digest, low in fat |
| Plain white rice or potato | Yes | Simple carbohydrate, gentle on the gut |
| Fresh food with whole ingredients | Yes | Digestible, no unnecessary additives |
| High-fat kibble or rich wet food | No | Hard to digest, worsens diarrhoea |
| Raw food | No | Increased pathogen risk when gut is compromised |
| Dairy or sugary treats | No | Can worsen gut inflammation |
Every dog is different — build your personalised Marleybones feeding and health plan tailored to your dog's age, size, and health requirements.
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FAQs
Can humans catch giardia from an infected dog?
Yes, but the risk is low. The strain of giardia most common in dogs (assemblage C and D) is different from the strain that typically infects humans (assemblage A and B). Cross-species transmission is possible but uncommon. Basic hygiene — washing hands after handling a dog, their stools, or their bedding — is sufficient precaution for most households.
How long does it take for a dog to recover from giardia?
Most dogs show improvement within a week of starting antiparasitic treatment. Full resolution of symptoms, including normal stools, takes one to three weeks. Some dogs continue to shed cysts for a short period after symptoms clear, which is why a follow-up stool test is worth requesting from your vet.
Does giardia go away on its own in dogs?
Occasionally in healthy adult dogs with strong immune systems, but this is not reliable. Untreated giardia causes ongoing gut inflammation, poor nutrient absorption, and weight loss. It also poses a risk to other animals in the household. Veterinary treatment is the safe and appropriate course of action.
Can I use a probiotic to help my dog recover from giardia?
Probiotics do not treat giardia, but they support gut recovery after antiparasitic medication, which can disrupt the normal gut microbiome. Prebiotic fibre — found in ingredients like chicory root — feeds beneficial bacteria and helps restore a healthy gut environment. Use probiotics and prebiotics alongside, not instead of, prescribed treatment.
Should I change my dog's food permanently after a giardia infection?
Not necessarily. If your dog's diet was working well before the infection, returning to it gradually after recovery is fine. If recurring gut issues suggest a more sensitive digestive system, a move to a cleaner, more digestible diet long-term is worth considering. Talk to your vet if you are unsure.
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