Why do my dog‘s farts smell so bad?

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The short answer!

Smelly wind comes from sulphur compounds produced when gut bacteria break down protein.

The smell comes down to chemistry. When gut bacteria ferment undigested food in the large intestine, they produce gases - including hydrogen sulphide and other sulphur compounds responsible for that rotten-egg smell (1).

What makes it worse

Protein-rich diets produce more sulphur compounds during digestion. Poor quality proteins that aren't fully absorbed in the small intestine give bacteria more material to ferment. Eggs, red meat, and cruciferous vegetables (broccoli, cabbage) are common culprits.

Dairy is another trigger - many adult dogs lack enough lactase to digest it properly, leaving lactose to ferment in the gut.

Gut bacteria matter

An imbalanced microbiome can shift fermentation patterns toward smellier byproducts. This often happens after antibiotics, dietary changes, or digestive upsets. Dogs with consistent, balanced gut bacteria tend to produce less offensive wind.

When smell signals something more

Occasional stinky farts are normal. Persistent foul odour alongside loose stools, appetite changes, or weight loss suggests malabsorption or underlying digestive issues worth investigating with your vet.

References

  1. Pilla R, Suchodolski JS. The role of the canine gut microbiome and metabolome in health and gastrointestinal disease. Front Vet Sci. 2020;6:498. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6971114/

This content is for general information only and does not replace veterinary advice. Supplements and nutritional products are not licensed veterinary medicines. Always speak to your vet before making changes to your dog’s diet, supplements, or care routine.

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owners also ask

What causes really stinky wind in dogs?

Sulphur-rich foods, poor protein digestion, gut bacteria imbalances, and food intolerances are the main drivers. The smellier the wind, the more undigested material is being fermented in the large intestine.

Can probiotics for dogs powder help with smelly wind?

Yes. Probiotics can help rebalance gut bacteria, reducing the fermentation patterns that produce sulphur-heavy smells. Powder formats mix easily into food and suit dogs with sensitive digestion.

Are dog probiotic chews or powder better for digestive issues?

Powder is generally better for digestive issues. It contains fewer additives, mixes into existing meals, and suits sensitive stomachs. Chews are convenient but often include binders and flavourings that can irritate already-unsettled guts.