--- topic: "Mouthwash" title: "Is Mouthwash Good or Bad for You?" order: 1 description: "What mouthwash does for plaque and gums, why antiseptic rinses may disrupt helpful mouth bacteria and nudge blood pressure, and when a rinse is worth using." question: "Is mouthwash good or bad for you?" answer: "Mouthwash likely lowers plaque and gum inflammation a little, but small trials link antiseptic rinses to shifted mouth bacteria and slightly higher blood pressure." actions: - "Treat mouthwash as an add-on to brushing and cleaning between your teeth, not a replacement. Trials test rinses as an adjunct to mechanical cleaning [1]." - "Ask a dentist whether a fluoride rinse suits your children or teens. In trials, supervised use cut new decay in permanent teeth by about 27% [2]." - "Keep antiseptic rinses to once a day or less, and chlorhexidine to dentist-recommended courses, as 4+ weeks causes tooth staining [1]; one cohort saw risk signals with twice-daily use [3]." cautions: - "If you have high blood pressure, ask your clinician before using an antibacterial rinse daily: in 15 treated hypertensive adults, three days raised systolic pressure by 2.3 mmHg [4]." - "If you smoke, drink heavily or have had an oral cancer, consider alcohol-free rinses. Alcohol rinses raised salivary acetaldehyde, though a meta-analysis found no significant overall cancer link [5][6]." confidence: 3 confidenceNote: "Plaque and gum effects are supported by Cochrane-level evidence; the blood pressure and diabetes signals rest on small short trials and observational data, mostly with chlorhexidine." evidenceSummary: rctCount: 1 observationalCount: 2 metaAnalysisCount: 4 totalParticipants: "60,000+" replicated: true newestStudyYear: 2023 references: - id: "1" pmid: "28362061" title: "Chlorhexidine mouthrinse as an adjunctive treatment for gingival health" authors: "James P, Worthington HV, Parnell C, et al." year: 2017 journal: "Cochrane Database Syst Rev" - id: "2" pmid: "27472005" title: "Fluoride mouthrinses for preventing dental caries in children and adolescents" authors: "Marinho VC, Chong LY, Worthington HV, et al." year: 2016 journal: "Cochrane Database Syst Rev" - id: "3" pmid: "28939409" title: "Over-the-counter mouthwash use and risk of pre-diabetes/diabetes" authors: "Joshipura KJ, Muñoz-Torres FJ, Morou-Bermudez E, et al." year: 2017 journal: "Nitric Oxide" - id: "4" pmid: "25359409" title: "Antibacterial mouthwash blunts oral nitrate reduction and increases blood pressure in treated hypertensive men and women" authors: "Bondonno CP, Liu AH, Croft KD, et al." year: 2015 journal: "Am J Hypertens" - id: "5" pmid: "19444911" title: "Salivary acetaldehyde increase due to alcohol-containing mouthwash use: a risk factor for oral cancer" authors: "Lachenmeier DW, Gumbel-Mako S, Sohnius EM, et al." year: 2009 journal: "Int J Cancer" - id: "6" pmid: "34360508" title: "Mouthwash Use and the Risk of Oral, Pharyngeal, and Laryngeal Cancer. A Meta-Analysis" authors: "Hostiuc S, Ionescu IV, Drima E" year: 2021 journal: "Int J Environ Res Public Health" - id: "7" pmid: "31058336" title: "Efficacy of adjunctive anti-plaque chemical agents in managing gingivitis: A systematic review and network meta-analyses" authors: "Figuero E, Herrera D, Tobías A, et al." year: 2019 journal: "J Clin Periodontol" - id: "8" pmid: "32210245" title: "Effects of Chlorhexidine mouthwash on the oral microbiome" authors: "Bescos R, Ashworth A, Clarke C, et al." year: 2020 journal: "Sci Rep" - id: "9" pmid: "23183324" title: "Physiological role for nitrate-reducing oral bacteria in blood pressure control" authors: "Kapil V, Haydar SM, Pearl V, et al." year: 2013 journal: "Free Radic Biol Med" - id: "10" pmid: "31542940" title: "Influence of mouth rinse use on the enterosalivary pathway and blood pressure regulation: A systematic review" authors: "Senkus KE, Crowe-White KM" year: 2020 journal: "Crit Rev Food Sci Nutr" - id: "11" pmid: "37867065" title: "Mouthwash Effects on the Oral Microbiome: Are They Good, Bad, or Balanced?" authors: "Brookes Z, Teoh L, Cieplik F, et al." year: 2023 journal: "Int Dent J" - id: "12" pmid: "31709856" title: "Over-the-counter mouthwash use, nitric oxide and hypertension risk" authors: "Joshipura K, Muñoz-Torres F, Fernández-Santiago J, et al." year: 2020 journal: "Blood Press" --- Mouthwash does what it is meant to do: antiseptic rinses lower plaque and gum inflammation a little on top of brushing [1][7]. The trade-offs are less known. A week of chlorhexidine rinse shifted mouth bacteria and lowered nitrite, a molecule the body can turn into a vessel-relaxing signal [8][9]. Small trials saw systolic blood pressure rise a few points [9][4]. Brushing and cleaning between teeth remain the foundation. ## How it works ### What rinses do for teeth and gums - **Chlorhexidine** is the best-studied antiseptic rinse. In 51 trials with 5,345 people, it cut plaque substantially and gingivitis slightly, but it stained teeth, and taste changes were commonly reported [1]. - **Essential-oil rinses** and cetylpyridinium chloride (CPC) rinses are other common active types. In a network meta-analysis of 6-month home-use trials, essential-oil rinses had the greatest effect on gum inflammation of the active agents [7]. - **Fluoride rinses** prevent cavities. In 37 trials with 15,813 children and teens, mostly supervised school programs, new decay fell about 27% [2]. ### The nitrate pathway and the microbiome Bacteria in the mouth turn nitrate (from food and the body's own chemistry) into nitrite, which can be converted into nitric oxide, a signal that relaxes blood vessels. An antiseptic rinse suppresses these bacteria. In 19 healthy volunteers, a week of chlorhexidine mouthwash cut oral nitrite production by 90% and plasma nitrite by 25%, and blood pressure rose 2 to 3.5 mmHg [9]. A systematic review of five human crossover studies found lower salivary nitrite in all five (plasma nitrite in three) and higher blood pressure in four [10]. A one-week chlorhexidine course also shifted salivary bacteria and made saliva more acidic [8]. A review describes this as "dysbiosis", though much remains unknown [11]. ### Alcohol and cancer Alcohol-containing rinses increase salivary acetaldehyde, a cancer-linked by-product of ethanol [5]. But a meta-analysis of 17 studies found no significant overall link between mouthwash and head and neck cancer [6]. ### When a rinse makes sense A short chlorhexidine course for stubborn plaque or gingivitis that a dentist recommends [1], or a fluoride rinse for children if a dentist advises it [2]. Otherwise it is optional. For the bigger picture, see [Your Mouth's Hidden Ecosystem](/oral-microbiome/your-mouths-hidden-ecosystem), [Nitric Oxide](/nitric-oxide/cardiovascular-signaling) and [Blood Pressure](/blood-pressure/natural-management). ## The evidence in detail ### Plaque and gingivitis A Cochrane review of 51 randomized trials (5,345 participants) tested chlorhexidine as an add-on to routine cleaning for at least 4 weeks. After 4 to 6 weeks, the Gingival Index (0 to 3) fell by 0.21 (95% CI 0.11 to 0.31) in 10 trials with mild inflammation (805 people, high-quality evidence), which the authors did not consider clinically relevant. Plaque was far lower, by 1.45 standard deviations (1.00 to 1.90; 12 trials, 950 people). Staining increased by 1.07 standard deviations (0.80 to 1.34). Taste disturbance, mucosal soreness or peeling, and burning were commonly reported. Fifty of 51 trials were at high risk of bias, though the authors judged further research unlikely to change the plaque and gingivitis estimates [1]. A network meta-analysis of 53 six-month trials (19 of rinses in 5,775 people, 32 of toothpastes in 2,682) found that essential-oil, triclosan-copolymer, chlorhexidine (0.10% or more) and CPC (above 0.05%) rinses had the greatest effect [7]. For fluoride rinses, 37 trials in 15,813 children gave a pooled prevented fraction of 27% (23% to 30%), though 28 trials were at high risk of bias [2]. ### Blood pressure In Kapil's study, 19 healthy volunteers spent 7 days on a control period and then 7 days using a chlorhexidine rinse. Oral nitrite production fell 90%, plasma nitrite 25% (p = 0.001), and systolic and diastolic pressure rose 2 to 3.5 mmHg within a day, tracking the nitrite drop (r squared 0.56). The control period always came first, so the design was not randomized [9]. In a randomized crossover trial, 15 treated hypertensive adults (mean age 65) used antibacterial mouthwash or water for 3 days. Systolic pressure was 2.3 mmHg higher (0.5 to 4.0), diastolic was unchanged, and the plasma nitrite fall was borderline (p = 0.09) [4]. A systematic review of eight studies (five human crossover studies and three animal studies) found blood pressure rose in four of the five human studies; effects varied with rinse strength and composition [10]. ### Observational links In the San Juan cohort, 945 overweight or obese adults aged 40 to 65 were followed for 3 years. Mouthwash twice a day or more went with a higher risk of pre-diabetes or diabetes (incidence rate ratio 1.55 versus lighter users; 1.21 to 1.99), with no association below twice daily [3]. In 540 people free of hypertension, 66 (12%) developed it, with a ratio of 1.85 (1.17 to 2.94) for twice-daily use versus lighter use. Blood pressure at a single visit showed no association [12]. These are self-reported habits in one population, and confounding cannot be excluded. ### Microbiome In 36 healthy people, 7 days of chlorhexidine twice daily after a placebo week raised Firmicutes and Proteobacteria and lowered Bacteroidetes, TM7, SR1 and Fusobacteria. Saliva pH and buffering fell, lactate and glucose rose, nitrite fell, and systolic pressure trended up. The design was single-blind and not randomized [8]. A narrative review notes that effects on fungi and viruses are barely studied [11]. ### Cancer Thirteen ready-to-use mouthwashes were tested in four volunteers. Salivary acetaldehyde averaged 41 micromolar half a minute after rinsing, within the range seen after alcoholic drinks. The estimated lifetime cancer risk from systemic exposure was 3 in a million, with a margin of exposure of 217,604 that would be seen as a low public health concern. Local levels in saliva, however, reached concentrations linked to DNA damage in cell studies [5]. A meta-analysis of 17 studies (17,085 cases, 20,032 controls) found no significant difference between users and non-users, and alcoholic rinses showed no excess. Frequent use showed a marginal increase [6]. ### Where the evidence conflicts Plaque benefits are well established. The blood pressure trials are small and used chlorhexidine or unspecified antibacterial rinses, and effects differed by rinse strength and composition [10]. The diabetes and hypertension associations come from one cohort. None of this proves harm from ordinary alcohol-free or essential-oil rinses. ### Bottom line Confidence 3 of 5. Mouthwash helps a little with plaque and gum inflammation, and fluoride rinses help prevent cavities in children. Daily antiseptic use alters the mouth's bacteria and may nudge blood pressure, so make it a targeted tool rather than a habit.