Mouthwash ingredients proven to fight bad breath.

- chlorhexidine, chlorine dioxide (sodium chlorite), zinc chloride, cetylpyridinium, triclosan, essential oils/antiseptic formulations. | How these compounds work. | Brands of oral rinses that contain these ingredients.


Link to types of oral rinses.

What are the most effective mouthwash ingredients for treating halitosis?

If you've ever looked at the list of active ingredients found in the different kinds of mouthwashes sold as a control for bad breath, you might wonder which ones are the most effective and how each one works.

That's the subject of this page. It outlines how the compounds most frequently found in mouthwash formulations create their effect. And provides some of the scientific evidence that both that information, and each compound's claim for effectiveness, are based on.

What ingredients do we cover?


While researching this subject, it was our impression that the following compounds are the ones most frequently used as the active ingredient(s) in mouthwash formulations designed to combat halitosis.

chlorhexidine, cetylpyridinium, chlorine dioxide, zinc chloride, triclosan, essential oils/antiseptic formulations.

Product listings.

This page also lists mouthwash products and brands we've noticed that contain these ingredients in their formulation.

How do these compounds work?

a) Usually one of two mechanisms is involved.

When it comes to mouthwash ingredients and their effect on halitosis, the mode of action of the compound is usually based on one of the following abilities:

1) Antibacterial agents.

Since it's anaerobic bacteria living in your mouth that create the smelly compounds that cause bad breath, mouthwashes that contain antibacterial agents can help to reduce their numbers, and therefore aid in reducing malodor.

  • Ingredients to look for - Chlorhexidine, cetylpyridinium chloride and/or triclosan are antibacterial compounds frequently included in the formulations of mouthwashes.
2) Ingredients that affect VSC formation.

VSC's (volatile sulfur compounds) are the smelly molecules responsible for the stench of bad breath. So any compound that's effective in neutralizing them, will help to improve the quality of your breath.

  • Ingredients to look for - Chlorine dioxide (sodium chlorite) and zinc compounds have been demonstrated to have an affect on VSC's.

b) Combination formulations have been shown to be the best.

Research shows that the most effective mouthrinses for halitosis employ a multifaceted approach. They contain a combination of ingredients, so they're able to take on a person's breath odor problems on more than one front simultaneously.

c) Other kinds of products use these same ingredients for odor control.

Besides just mouthwashes, other types of products can serve as a delivery system for the compounds discussed on this page. They include: mints, lozenges, sprays, drops, gum and toothpaste.

Picture of a bottle of mouthwash.

Mouthwash ingredients proven effective in helping to control bad breath.

1) Antibacterial compounds -

a) Chlorhexidine gluconate.

Properties: Antibacterial

Chlorhexidine gluconate is a broad-spectrum antibacterial compound. It's commonly used in dentistry in the treatment of gum disease. As a treatment for halitosis, it provides a benefit by killing bacteria that produce smelly VSC's.

The most common formulation of this compound is a 0.12% oral rinse (Peridex®, Perioguard®), available by prescription only (such as from your dentist).


In terms of effectiveness in treating bad breath, chlorhexidine is generally considered to be the gold standard of oral rinses.

  • Several studies have demonstrated that the use of a 0.2% solution can produce a significant reduction in VSC levels, for over 3 hours. (Some studies suggest that some level of effect lasts for as long as 12 hours.) The use of a 0.12% rinse (the most common formulation) tends to create a similar but less robust benefit.

    This prolonged effect is due to the fact that chlorhexidine is adsorbed onto oral surfaces (it binds to the surface of tissues). Then, over time, it is gradually released into the oral cavity.

  • Its antimicrobial effects also help to create a reduction in breath odor over the long-term. (It's use can reduce plaque formation on the order of 35 to 60%.)

Section references - Cortelli, Lourith, Amoian

Side effects.

Unfortunately, the use of chlorhexidine mouthwash creates some noticeable side effects. And for that reason it should only be used under the supervision of a dentist, especially when its long-term use is planned. Issues of concern are:

  • Temporary but noticeable staining of the user's tongue and teeth. A professional dental cleaning is usually required to remove the discoloration from tooth surfaces.
  • It tends to alter the user's sense of taste. The compound itself also has a bad taste.
  • It's use tends to increase tartar formation. Extended use may result in tissue irritation.

Section references - Fedorowicz, Cortelli

Chlorhexidine products to look for:
  • Peridex®, Perioguard®, Paroex® - chlorhexidine gluconate
  • Perio-Aid® - chlorhexidine + cetylpyridinium chloride
  • Halita® - chlorhexidine + cetylpyridinium chloride + zinc lactate

[See "best to use" page for comparisons about effectiveness.]

b) Cetylpyridinium chloride.

Properties: Antibacterial

Cetylpyridinium chloride is an antibacterial compound that helps to reduce breath odors by way of helping to control the number of VSC-producing anaerobic bacteria living in a person's mouth.

Effectiveness in mouthwash.

Studies suggest that the antibacterial affect of cetylpyridinium chloride (CPC) isn't as robust as chlorhexidine's.

  • A study by Ayad determined that the use of a 0.075% CPC mouthrinse (Crest Pro-Health® mentioned below contains this concentration) over a 6-month period reduced plaque accumulation scores on the order of 35%. (Reductions produced by chlorhexidine can be up to 60%.)
  • Its effect on VSC levels was found to last for only 3 hours, as compared to up to 12 hours for chlorhexidine.

    However, simply rinsing with a CPC product more frequently throughout the day could be a method of overcoming this shortcoming.

Research suggests that when combined with other compounds (especially with zinc alone, or in combination with chlorhexidine too) a synergistic (more effective) action is created. (You'll see below that many mouthwash formulations take advantage of this phenomenon.)

Section references - Ayad, Fedorowicz, Cortelli

Something you probably didn't know.

Because this compound is safe for use in breath-odor products for cats and dogs, it is overwhelmingly the most-used agent for oral malodor control.

Section references - Lourith

Cetylpyridinium products to look for:
  • Crest Pro-Health®, Scope®, Cepacol®, Colgate Plax®, Act Advanced Care®, KForce Balance® - cetylpyridinium chloride
  • Breath Rx® - cetylpyridinium chloride + zinc + essential oils
  • Perio-Aid® - chlorhexidine + cetylpyridinium chloride
  • Halita® - chlorhexidine + cetylpyridinium chloride + zinc lactate

[See "best to use" page for comparisons about effectiveness.]

c) Essential oil preparations.

Properties: Antibacterial

Essential oil mouthrinses are typically water/alcohol solutions of menthol, eucalyptol, thymol and/or methyl salicylate.

These products have a history of being used in the treatment of gum disease. When used for that purpose or the treatment of halitosis, the basis of their effect is due to their antibacterial properties.

The most common form of this kind of preparation is the "antiseptic" mouthwash (e.g. Listerine® or one of its many generic equivalents). The typical formulation is: 0.092% eucalyptol, 0.042% menthol, 0.06% methyl salicylate and 0.064% thymol in a solution containing 21.6% to 26.9% alcohol.

Effectiveness as a mouthwash.

Studies suggest that:

  • The initial effect (first 60 minutes) of using this type of preparation is simply re-odorization, meaning that the essential oils act as masking agents that just cover over the person's breath odor.
  • At post treatment times of 2 to 3 hours, the anti-odor activity of these products is more likely due to their antibacterial action.
  • Long term use of an essential oil rinse can help to maintain reduced levels of VSC producing bacteria (both living in dental plaque associated with teeth and gums, and in the coating that builds up on the tongue). Dental plaque reductions lie on the order of 20 to 55%.
  • A part of the effectiveness of essential oils apparently stems from their ability to permeate into the depths of oral biofilms to a greater degree than other types of compounds.

Section references - Cortelli, Gera


Despite its effectiveness in killing bacteria, this type of mouthwash may not make the best choice for treating bad breath:

  • Antiseptic preparations typically contain high levels of alcohol (around 25% ethanol). Alcohol is a desiccant and therefore creates a drying effect on oral tissues, a phenomenon that typically aggravates a person's breath problems.

    (Follow this link for more details about how dry mouth conditions contribute to oral malodor.)

  • High alcohol levels may create an unpleasant burning sensation for some people, thus lowering their compliance in using the rinse.
  • Ethanol may be metabolized into smelly compounds, thus increasing breath malodor.

Section references - Lourith

Essential oils products to look for:
  • Listerine® - essential oils
  • Generic "antiseptic" mouthwashes (of which there are many) - essential oils
  • Breath Rx® - cetylpyridinium chloride + zinc + essential oils

[See "best to use" page for comparisons about effectiveness.]

d) Triclosan.

Properties: Antibacterial

Triclosan is an antimicrobial compound that reduces VSC formation by way of reducing the level of bacteria that create them. Besides just mouthwash, it's also found in other oral care products.


Concerns have been raised about the safety of using products formulated with triclosan. Use this link for further discussion.

Triclosan products to look for:
  • Breeze® - triclosan, zinc

2) Compounds that affect VSC formation. -

As opposed to an antibacterial approach, another way to combat halitosis is to have an affect on the smelly molecules (VSC's) that are responsible for it.

a) Chlorine dioxide (or sodium chlorite).

Properties: Affects Volatile Sulfur Compound Formation, Anitibacterial

Chlorine dioxide (ClO2) is an oxidizing agent that's able to degrade sulfur-based amino acids. Since these are the building blocks of the volatile sulfur compounds that cause bad breath, when fewer of them are available to bacteria, fewer smelly VSC's are formed.

As an additional mechanism, chlorine dioxide also has antimicrobial properties and therefore can help to reduce the number of bad-breath causing bacteria living in a person's mouth.

  • The one-time use of a mouthrinse containing 1.0% sodium chlorite was found to be effective in reducing VSC levels for a period of 8 hours and beyond.
  • Combination mouthwashes (such as chlorine dioxide + zinc) are likely more effective than the use of either component alone.

Section references - Frascella, Fedorowicz

Chlorine dioxide products to look for:

There seems to be no shortage of brands of these types of rinses, or advertising hype to go along with them. Some mouthwashes are formulated with sodium chlorite as the active ingredient, which then breaks down to release chlorine dioxide.

  • CloSYS®, ProFresh®, TheraBreath®, DioxiCare® - chlorine dioxide
  • TriOral®, SmartMouth®, Oxygene®, Oxyfresh® - chlorine dioxide + zinc

[See "best to use" page for comparisons about effectiveness.]

b) Zinc.

Properties: Affects Volatile Sulfur Compound Formation

Metal ions (such as zinc, sodium, tin, copper, and magnesium) have the ability to oxidize (react with) the thiol (sulfur based) molecule groups found on the precursor components of VSC's. (FYI: Thiol's are the smelly compounds added to natural gas to give it its stinky smell.)

Section references - Cortelli

As a possible second benefit, studies suggest that zinc also has antibacterial properties. The compound used in a mouthwash's formulation might be zinc chloride, lactate, acetate, citrate or nitrate.

Section references - Dadamino

Effectiveness in mouthwash.

Zinc is the metal of choice for rinses used to treat bad breath. Not because it's the most effective one (copper is) but because it provides a benefit, yet has low toxicity and does not create tooth staining (like other metals can, especially tin and copper).

  • Studies have shown that 1% zinc acetate mouthwash has a significant effect on VSC levels, even 3 hours after use.
  • It's common for rinses to include zinc as one of its active ingredients (combination treatment).

Section references - Cortelli


Some people may notice that mouthwashes that contain zinc compounds have a metallic taste or odor. (Most products contain masking agents that are able to keep this issue in check.)

Zinc products to look for:
  • Halita® - chlorhexidine + cetylpyridinium chloride + zinc lactate
  • Breath Rx® - cetylpyridinium chloride + zinc + essential oils
  • TriOral®, SmartMouth®, Oxygene®, Oxyfresh® - chlorine dioxide + zinc
  • Breeze® - triclosan, zinc

[See "best to use" page for comparisons about effectiveness.]

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Mouthrinses for bad breath and their active ingredients.

We've done our best to organize the following list but we must leave it to the reader to confirm these details when making their purchase.

  • Peridex®, Perioguard®, Paroex® - chlorhexidine gluconate
  • Perio-Aid® - chlorhexidine + cetylpyridinium chloride
  • Halita® - chlorhexidine + cetylpyridinium chloride + zinc lactate
  • Listerine® and generic "antiseptic" mouthwashes (of which there are many) - essential oils
  • Breath Rx® - cetylpyridinium chloride + zinc + essential oils
  • Crest Pro-Health®, Scope®, Cepacol®, Colgate Plax®, Act Advanced Care®, KForce Balance® - cetylpyridinium chloride
  • TriOral®, SmartMouth®, Oxygene®, Oxyfresh® - chlorine dioxide + zinc
  • CloSYS®, ProFresh®, TheraBreath®, DioxiCare® - chlorine dioxide
  • Breeze® - triclosan, zinc

It's important that the manufacturer's instructions and recommendations are followed when using these products.

[See "best to use" page for comparisons about effectiveness.]

So any mouthwash that contains some of ingredients listed above should be effective in curing bad breath?

No, not necessarily.

a) Some mouthwash formulations are more effective than others.

From a standpoint of research evidence, some products have been shown to be more effective than others. In fact, there have been a couple of published literature reviews that have investigated this subject and have reported their findings.

We have an entire page dedicated to what they found. Here's the link: Effective mouthwashes for halitosis, as documented by research studies.

b) The use of mouthwash alone is seldom an adequate cure.

We think it's important to point out that even the best formulations for treating halitosis can't really be expected to provide a complete cure.

That's because they can't, just on their own, address all of the issues that apply in most people's cases. We explain in greater detail here.

If you haven't been there already, don't overlook our page that discusses what research shows is the most effective type of mouthwash for bad breath.

Or our page describing how other products other than just mouthwash can be used as a delivery system for compounds shown to be effective against bad breath.



Tonsil stones??

Why is there no mention of tonsil stones as a source of bad breath? They seem to be mostly ignored in dentist offices. It was by accident that I found out about them and now I check for them daily because they are very smelly.

Informative Article

This was the most informative article that I have read about oral hygiene.

Thanks AG.

Thanks AG.