Dog Water Additives for Bad Breath: Do They Work?

TL;DR

A dog water additive is a liquid you add to the water bowl that works chemically on mouth bacteria, a bit like a mouthwash your dog drinks. Several are accepted by the Veterinary Oral Health Council (VOHC) for plaque or tartar, and controlled studies show modest reductions in buildup. Additives have no scrubbing action, so they work best alongside brushing or a dental chew, and they cannot remove tartar or fix gum disease. Use only products made for dogs, at the label's dilution.

How water additives work

The authors of a 2023 water additive trial put it plainly: brushing, kibble and dental chews control plaque and tartar through mechanical action, but "water additives do not have such properties." Their effect depends on the chemistry of the ingredients, which vary by brand.

That is why additives tend to show smaller effects than brushing, and why they are usually recommended as part of a routine rather than the whole routine.

What the studies show

• A 2023 randomized study of 40 dogs gave a pomegranate-based water additive (Vet Aquadent FR3SH, Virbac) or nothing for 30 days after a professional cleaning. Plaque and tartar were significantly lower in the additive group, and gum bleeding improved more. The study was financed by Virbac.
• A 2020 pilot crossover trial ran for 208 days, with each dog spending 90 days on a xylitol-based drinking water additive and 90 days without. The additive reduced the average plaque score by 5.1% and the average tartar score by 14.9%.
• A 2016 study of an additive containing plant enzymes and green tea found 22% less plaque over 28 days, but dogs were not randomly assigned to groups, which weakens the result.
• A 2025 study of dogs that had not had a professional cleaning found that a water additive improved gum health when combined with weekly brushing or a daily dental chew. The study was funded by Virbac.

VOHC-accepted water additives

As of August 2026, additives on the VOHC list for dogs include:

• HealthyMouth Water Additive for Dogs and related HealthyMouth additives, plaque
• TropiClean Fresh Breath Dental Water Additive and its Max Strength, Gut Health, Hip & Joint and Skin & Coat versions, plaque
• Naturél Promise Fresh Dental Water Additive, plaque
• Vetradent Liquid Water Additive, tartar
• Plaqtiv+ Oral Care Water Additive, tartar
• Bluestem Water Additive, tartar
• Skout's Honor Water Additive, tartar
• Virbac C.E.T. Aquadent FR3SH, plaque and tartar

Note which claim each product has. A "plaque" seal and a "tartar" seal are separate awards. Check the current list for the exact product.

Safety tips

• Use only pet products. VCA warns that human mouthwashes are toxic to pets.
• Follow the dilution on the label. Some dog water additives contain xylitol at low concentrations, like the one in the 2020 pilot study. The FDA warns that xylitol in human products such as sugar-free gum and toothpaste can cause a dangerous drop in blood sugar in dogs. Never add anything to the bowl that was made for people.
• Make sure your dog keeps drinking. VCA notes that most dogs don't mind the taste, but not all accept it. If your dog drinks noticeably less, stop and try another option. This matters most for older dogs and dogs with kidney disease.
• Shared bowls. VCA notes that pet-approved additives are generally fine if a cat drinks some too, but check the label.
• Refresh the water as often as the label directs, and mix a fresh dose each time.

When an additive is not enough

Bad breath that persists usually means plaque has already hardened into tartar or the gums are infected. VCA notes that tartar needs professional scaling under anesthesia. See a vet if you notice brown tartar, red or bleeding gums, dropped food, chewing on one side or a sudden change in breath. VCA also notes that kidney disease can cause bad breath.

How to build a routine around an additive

1. Start with clean teeth. Several of the additive trials began right after a professional cleaning.
2. Add the additive daily to fresh water.
3. Add something mechanical: daily brushing if possible, or a VOHC-accepted chew. See best dog chews for bad breath.
4. Recheck at your dog's next exam. The AAHA guidelines consider an awake oral exam every 6 months appropriate.

FAQ

Do dog water additives really work for bad breath?

The VOHC-accepted ones reduced plaque or tartar in trials, and less plaque usually means fresher breath. The effects are modest, so pair an additive with brushing or chews.

Are water additives safe for older dogs?

Generally, if your dog keeps drinking normally and the product suits any health conditions. Ask your vet first if your dog has kidney disease or other illnesses where water intake matters.

Water additive or dental powder?

Both work chemically and suit dogs that resist brushing. An additive needs a dog that drinks reliably from its own bowl; a powder needs a dog that eats its meal. See best dog dental powder.

References

• Gawor JP, Ziemann D, Nicolas CS. A water additive with pomegranate can reduce dental plaque and calculus accumulation in dogs. Frontiers in Veterinary Science. 2023. PMID: 37841470
• Lowe C, Anthony J. Pilot study of the effectiveness of a xylitol-based drinking water additive to reduce plaque and calculus accumulation in dogs. Canadian Veterinary Journal. 2020. PMID: 31892757
• Lindinger MI. Reduced dental plaque formation in dogs drinking a solution containing natural antimicrobial herbal enzymes and organic matcha green tea. Scientifica. 2016. PMID: 27867678
• Gawor J, Jank M, Harvey CE, Nicolas CS. Effectiveness of dental homecare protocols in unscaled dogs. Journal of Veterinary Dentistry. 2025. PMID: 39587858
• Veterinary Oral Health Council. VOHC Accepted Products for Dogs. List updated August 2026.
• U.S. Food and Drug Administration. Paws off xylitol; it's dangerous for dogs.
• VCA Animal Hospitals. How to choose puppy dental treats, Plaque and Tartar Prevention in Dogs, Causes of bad breath in puppies.
• American Animal Hospital Association. 2019 AAHA Dental Care Guidelines: regular oral healthcare.