07/02/2026
Giardia does not require metronidazole!
BEST ADVICE FOR GIARDIA IN DOGS...
Looking for an alternative, natural and EFFECTIVE treatment to Giardia infection in cats and dogs? Use S. boulardii.
Listen to this - studies show S. boulardii, a soil-based probiotic, is as effective as Metronizadole at clearing Giardia in dogs only its side effects include reducing the damage caused by infection, preserving gut integrity AND inhibiting oxidative stress that results from the parasite with metro! Other studies show S. boulardii helps the gut biome to stabilise and recover, unlike Metro which annihilates it, leaving the door open to re-infection.
"The effect of treatment with S. boulardii with or without metronidazole on the intestinal mucosa, the antioxidant defence system and the parasitic load was determined in experimental giardiasis. Eight groups of animals with infection and/or treatment with the probiotic and/or drugs for 1 week after infection with Giardia lamblia were used. A reduction of approximately 90% in the parasitic load was observed in ALL the treated groups. Saccharomyces boulardii attenuated the damage caused by infection in the intestinal mucosa preserving its architecture and inhibiting the oxidative stress induced by parasite and metronidazole."
https://enviromicro-journals.onlinelibrary.wiley.com/doi/abs/10.1111/jam.14941 #:~:text=Saccharomyces%20boulardii%20attenuated%20the%20damage,induced%20by%20parasite%20and%20metronidazole
Nor is this the first time probiotics have been used to kill off Giardia. Plenty of research here in humans show it to be a very effective approach (usually Sacchromyces with one or two species of Lactobacillus...) at resolving the issue
https://link.springer.com/article/10.1007/s00210-021-02124-z
In fact, I've yet to find a study of Metronizadole that has impressed me. For example, check this out - They did a randomized, double-blinded, placebo-controlled clinical trial on dogs comparing two treatments for dogs with acute diarrhoea: a probiotic combination and metronidazole. Sixty dogs were divided into three treatment groups. The time to resolution of diarrheal signs was evaluated using owner surveys and faecal scoring charts. Dogs presenting with acute diarrhoea achieved faecal normality in 3.5 days when receiving the probiotics and 4.6 days with the metronidazole (which, when you compare to doing NOTHING, taking 4.8 days to resolve, is really no different at all). While statistically they differences were not found to be signficant (p = 0.17), the main point is metronidazole is likely not any better than doing nothing (and probiotics seemed to do better...).
https://www.frontiersin.org/articles/10.3389/fvets.2019.00163/full
SYMPTOMS OF GIARDIA
Watery, unresolving, foul smelling diarrhoea though sometimes simply soft and greasy, often with gut pain and bloating.
HOW TO DETECT GIARDIA
Buy a rapid test for Giardia from an online supplier. Handy to have in the medikit. You will have the results in 10mins and can then treat, all from the comfort of your own home.
LONG TERM STRATEGY TO AVOID GIARDIA
Plenty of animals, human to dog, encounter Giardia daily and don't get the infection. The terrain has to be right. In this case, the gut (isn't it always). So a weakened / susceptible individual is, as ever, the very young, the very old, someone with gut sickness or an infection from something else which lowers the defences. I would add a poorly fed dog to this (chemically preserved dry kibble, for instance) which upsets the biome, rendering the animal susceptible to infection.
If your dog suffers recurring Giardia infections, that's the first place I'd look. Get the diet right, that's first. Get them on to real food and fet those poo scores up to 10/10, that's first.
Then, if still struggling, do a gut biome test (via poo sample) from any online supplier. They'll tell you if the biome is out of whack and will advise how to fix it. Some will say over the counter probiotics, some will give dietary advice, I'd try that to start.
If that doesn't work, FMT (faecal microbial transplantation) is, IMO, the best way to reset dogs gut flora to a positive (ie balanced) state. I use Legacy Biome in the US as it's produced by Margot Roman (aka Mashvet), the Queen of FMT. Very clean donors. Use discount code DOGSFIRST15 for 15% off your purchase.
If for more info and simple, home solutions to chronic gut issues in pets, join my membership (called "The Den) and sit in on monthly gut clinics where we discuss your dog's symptoms and set about finding the quickest, easiest solutions.
https://www.drconorbrady.com/offers/MGSTvZ4N
