Mouth Rinsing in Traditional Chinese Medicine: Ritual vs Reality

Before we had modern tools to measure bad breath, morning mouth rinsing was already part of Traditional Chinese Medicine (TCM) daily hygiene. It's an old habit that still feels strangely modern when you're standing over the sink at 6 a.m.

A recent bibliometric study on Chinese herbal medicine mouthwash research describes how oral-rinsing traditions evolved over millennia, with references to saltwater-style rinses going back as far as 2700 B.C.[1] But why does your mouth feel and smell so different in the morning?

The real reason morning breath happens

Morning breath is often blamed on "toxins" or overnight "waste", but the real story is: your mouth is an ecosystem whose chemistry changes on a clock.

Saliva runs on a schedule

While you sleep, salivary flow drops dramatically and saliva is one of your mouth's most important housekeeping fluids. Saliva is useful for diluting odor molecules, buffering acids, and helping control microbial buildup. According to the medical literature, unstimulated saliva follows a circadian rhythm, with meaningful shifts in flow across the day and very low output during sleep.[2]

That overnight dryness matters because many of the smells we label "morning breath" are volatile sulfur compounds (VSCs) such as hydrogen sulfide and methyl mercaptan, produced when oral bacteria break down proteins and debris.[3]

The tongue is a breeding ground for bacteria

The tongue's textured surface is basically a microbial apartment complex and "tongue coating" (that film you can sometimes see or feel) is strongly tied to oral malodor. When there's more coating, there's more substrate for VSC production and less saliva to wash the scene.[5][6] Morning breath is essentially a concoction of low-flow nighttime conditions plus a biofilm-friendly surface.

What actually helps?

Water: the simplest intervention with clinical data

A surprisingly simple intervention has clinical data behind it: water. In a randomised clinical trial, both rinsing with water (15 mL for 30 seconds) and drinking a glass of water (200 mL) produced statistically significant reductions in morning-breath measures, including organoleptic scores (yes, measurable by a real nose) and VSC readings measured by a portable gas-chromatography device.

Interestingly, there was no meaningful difference between "rinsing with water" and "drinking water" to the measured outcomes.[3] Hydration and dilution appear to be doing a lot of the heavy lifting.

A deeper clean with tongue cleaning

For something more effective, clean the tongue.

Clinical trials comparing approaches to "morning breath" consistently point to tongue cleaning as a key move. Scraping or brushing the tongue can reduce VSC levels, often noticeably in the short term.[4][5]

A systematic review of mechanical tongue cleaning found an overall positive effect on breath odor measures and tongue coating, while also noting that the evidence base is stronger for short-term outcomes than for long-term management of chronic halitosis.[6]

Where does Traditional Chinese Medicine stand?

Undoubtedly, TCM was the fresh morning breath trailblazer. A 2023 study on the topic discusses the long history of oral rinsing traditions and the evolution of mouthwash practices within TCM.[1]

A traditional, easy to implement method by TCM is to simply rinse with warm water every morning. Consistent, temperature-friendly to your enamel and an all encompassing swish. It's a simple solution by people who have been thinking seriously about oral hygiene rituals for a very long time.

A practical morning protocol

What does a practical, science-backed morning routine look like?

• rinse with warm water (or drink water)
• brush thoroughly
• brush your tongue and/or use a tongue scraper
• don't forget to floss as part of your regular routine

Want to make it feel a little more elevated? Use the sonic BON CHARGE Red Light Toothbrush, delivering near-infrared and red light to stimulate the health of your gums as part of your regular oral care routine.

BON CHARGE: This content is for general education and is not medical advice. Our products are not intended to diagnose, treat, cure, or prevent any disease. Always follow product instructions and consult a qualified healthcare professional for guidance tailored to you. Individual results may vary.

References

1. Zhou, F. et al. Characteristics of Chinese herbal medicine mouthwash clinical studies: a bibliometric and content analysis. J. Ethnopharmacol. 307, 116210 (2023). https://doi.org/10.1016/j.jep.2023.116210. PMID: 36736713. https://pubmed.ncbi.nlm.nih.gov/36736713/
2. Dawes, C. Circadian rhythms in human salivary flow rate and composition. J. Physiol. 220, 529–545 (1972). PMCID: PMC1331668. https://pmc.ncbi.nlm.nih.gov/articles/PMC1331668/
3. The effect of water on morning bad breath: a randomized clinical trial. J. Clin. Periodontol. (2015). PMID: 26081039. https://pubmed.ncbi.nlm.nih.gov/26081039/
4. Oliveira-Neto, J., Sato, S. & Pedrazzi, V. How to deal with morning bad breath: a randomized, crossover clinical trial. J. Indian Soc. Periodontol. 17, 757–761 (2013). PMID: 24554886. https://pubmed.ncbi.nlm.nih.gov/24554886/
5. Pedrazzi, V., Sato, S., de Mattos, M.G.C., Lara, E.H.G. & Panzeri, H. Tongue-cleaning methods: a comparative clinical trial employing a toothbrush and a tongue scraper. J. Periodontol. (2004). PMID: 15341360. https://pubmed.ncbi.nlm.nih.gov/15341360/
6. Van der Sleen, M.I., Slot, D.E. & Van der Weijden, G.A. Effectiveness of mechanical tongue cleaning on breath odour and tongue coating: a systematic review. Int. J. Dent. Hyg. (2010). PMID: 20961381. https://pubmed.ncbi.nlm.nih.gov/20961381/