There’s a small, easy-to-miss connection between two things you probably don’t think about together: your oral hygiene routine and your body’s own nitric oxide production.
The Bacteria in the Middle
As our complete guide to nitric oxide explains, eating nitrate-rich vegetables can help support nitric oxide production — but that conversion doesn’t happen entirely inside your blood vessels. Certain bacteria that live on your tongue and in your mouth play a real, necessary role, converting dietary nitrate into nitrite as a first step, before your body converts it further into nitric oxide.
Where Mouthwash Comes In
Regularly using antiseptic mouthwash may reduce the blood-pressure benefit of eating nitrate-rich vegetables over time, since certain mouth bacteria help convert that nitrate into nitric oxide. This isn’t a single study’s finding: a controlled trial in 19 healthy volunteers found that a full week of twice-daily antiseptic mouthwash use raised blood pressure by 2–3.5 mmHg, tracking closely with a drop in circulating nitrite (Kapil et al., 2013). A separate trial in adults already being treated for high blood pressure found a measurable systolic blood pressure increase (diastolic pressure did not change significantly) after just 3 days of antibacterial mouthwash use (Bondonno et al., 2015). Antiseptic (chlorhexidine-containing) mouthwashes are designed to reduce oral bacteria broadly — which is exactly why they can also interrupt this specific conversion pathway.
A real limit on what this evidence shows: both studies tested regular, sustained mouthwash use over several days — not a single use near one particular meal. Neither study measured whether using mouthwash once, near one meal, makes any meaningful difference. If you regularly eat nitrate-rich vegetables specifically to support this pathway, the more evidence-grounded takeaway is to think about how often you use an antiseptic mouthwash overall, not to focus on precise timing around any individual meal.
What This Doesn’t Mean
This doesn’t mean skipping oral hygiene — it’s a real, if still-emerging, reason to be thoughtful about how often you reach for an antiseptic rinse, not a reason to eliminate it. Oral health matters for its own well-established reasons, and this remains genuinely emerging research on a small, real effect — not a settled, universal rule. A recent 2026 systematic review pooling this research suggests the effect may be small enough to be of little practical significance for people with normal blood pressure specifically, while the strongest evidence for a real effect remains in people already being treated for high blood pressure.
One real point worth naming directly: if a dentist has prescribed you a chlorhexidine rinse for an active gum condition or infection, that prescribed treatment should take priority — this is general medical-safety reasoning (a diagnosed condition’s prescribed care outweighs a modest, not-yet-fully-established blood-pressure consideration), not a finding from a specific study. No published guidance was found either confirming or ruling out a real conflict here; when in doubt, this is a good question to bring to your dentist directly.
A Real, Still-Developing Area
A separate line of research has looked at tongue cleaning specifically: one study found that how often someone cleans their tongue is associated with real differences in their oral nitrate-processing bacteria. This isn’t a reason to change your tongue-cleaning habits — it’s simply a reminder that the mouth’s role in this pathway may extend a little beyond mouthwash alone, in an area that’s still being actively studied.
Researchers are also studying oral nitrate-reducing bacteria themselves as a possible future probiotic approach to blood pressure support — a real, active area of research, not yet an established recommendation.
Where This Fits
See our complete guide to nitric oxide for the complete picture, and our article on nitrate-rich foods for what to actually eat.
If blood pressure concerns or medication questions continue despite trying these routines, it’s worth talking with a doctor or other qualified professional.
References
- Chai, X., Liu, L., & Chen, F. (2024). Oral nitrate-reducing bacteria as potential probiotics for blood pressure homeostasis. Frontiers in Cardiovascular Medicine, 11, 1337281. https://doi.org/10.3389/fcvm.2024.1337281
- Kapil, V., Haydar, S. M. A., Pearl, V., Lundberg, J. O., Weitzberg, E., & Ahluwalia, A. (2013). Physiological role for nitrate-reducing oral bacteria in blood pressure control. Free Radical Biology & Medicine, 55, 93–100. https://doi.org/10.1016/j.freeradbiomed.2012.11.013
- Bondonno, C. P., Liu, A. H., Croft, K. D., Ward, N. C., Yang, X., Considine, M. J., Puddey, I. B., Woodman, R. J., & Hodgson, J. M. (2015). Antibacterial mouthwash blunts oral nitrate reduction and increases blood pressure in treated hypertensive men and women. American Journal of Hypertension, 28(5), 572–575. https://doi.org/10.1093/ajh/hpu192
- Toonen, R. et al. (2026). The effect of chlorhexidine mouthwash on blood pressure: A systematic review and meta-analysis. International Journal of Dental Hygiene, 24(3), 390–403. https://doi.org/10.1111/idh.70035
- Tribble, G. D., Angelov, N., Weltman, R., Wang, B.-Y., Eswaran, S. V., Gay, I. C., Parthasarathy, K., Dao, D.-H. V., Richardson, K. N., Ismail, N. M., Sharina, I. G., Hyde, E. R., Ajami, N. J., Petrosino, J. F., & Bryan, N. S. (2019). Frequency of tongue cleaning impacts the human tongue microbiome composition and enterosalivary circulation of nitrate. Frontiers in Cellular and Infection Microbiology, 9, 39. https://doi.org/10.3389/fcimb.2019.00039
About this article
Researched and written by: HealthUpward Editorial Team
Last updated: August 29, 2026
Evidence basis: Based on peer-reviewed research and reputable public health organizations cited within this article.
Medical review: This article has completed HealthUpward’s editorial review process. It has not been reviewed by a licensed healthcare professional.
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