Mouthwash sales are dominated by brand and habit, not evidence. Most over-the-counter mouthwashes give a sensation of cleanliness but do not change the trajectory of dental disease. A few — chlorhexidine after extraction, fluoride for orthodontic patients, lidocaine or benzydamine for ulcer pain — are genuinely useful, but each has a defined indication and a duration limit that pharmacy teams are well placed to communicate.

This guide summarises the evidence and counselling points for the main mouthwash classes available in UK community pharmacy, drawing on the BNF, NICE Clinical Knowledge Summaries, the Cochrane reviews on chlorhexidine and fluoride mouthrinses, and the Faculty of General Dental Practice toolkit.

Chlorhexidine — the post-procedure standard

Chlorhexidine gluconate is the most extensively studied antiseptic mouthwash. It binds to dental tissues and releases over hours, providing sustained antibacterial activity.

Common UK products:

• Corsodyl 0.2% (alcohol-containing and alcohol-free)
• Chlorohex 0.2%
• Curasept 0.05–0.2%

Evidence base:

The Cochrane review by James et al. (2017) concluded that chlorhexidine 0.12–0.2% mouthwash, used as an adjunct to mechanical plaque control, produces large reductions in plaque and moderate reductions in gingivitis over 4–6 weeks. The benefit is short-term; chronic use is not associated with sustained periodontal improvement.

Counselling points:

• Use 10 ml as a one-minute rinse twice daily
• Maximum 14 days continuous use; longer courses require dental supervision
• Reversible brown staining of teeth, restorations and tongue (mechanical removal at next dental visit)
• Taste alteration (usually mild)
• Avoid use within 30 minutes of toothpaste — sodium lauryl sulphate inactivates chlorhexidine
• Not first-line for routine plaque control in healthy mouths
• Children: usually after 7 years and only under dental advice

Indications where chlorhexidine adds value:

• After dental extraction (24 hours after the procedure, not before)
• Acute gingivitis or pericoronitis
• Aphthous ulcer prevention in selected cases
• Recurrent oral candidiasis (alongside antifungal treatment)
• Patients with a learning disability or physical impairment limiting mechanical hygiene

Fluoride mouthwash — caries prevention

Fluoride mouthwashes deliver a topical dose to high-risk patients in addition to fluoride toothpaste.

Common UK products:

• Colgate Fluorigard daily rinse (0.05% sodium fluoride)
• Sainsbury's, Boots, Tesco own-label
• Higher-strength weekly rinses (0.2% sodium fluoride) supplied by NHS dental services

Evidence base:

The Cochrane review (Marinho et al., 2016) showed a 27% mean reduction in caries increment in school-age children using daily or weekly fluoride mouthrinse versus placebo, with effect persisting over 2–3 year studies.

Indications:

• Children and adults with high caries risk
• Patients in fixed orthodontic appliances
• Adults with reduced saliva (Sjögren's syndrome, post-radiotherapy, polypharmacy-induced dry mouth)
• Patients with recurrent caries despite fluoride toothpaste
• Older adults with gum recession exposing root surfaces

Counselling:

• Use at a different time of day from toothpaste to extend topical exposure
• Do not eat or drink for 30 minutes after rinsing
• Children under 6 should generally not use mouthwash because of swallowing risk; supervised brushing with age-appropriate fluoride toothpaste is the standard advice
• Daily (0.05%) and weekly (0.2%) regimens are equivalent in evidence; daily often suits patient routine better

Hydrogen peroxide mouthwash

Hydrogen peroxide 1.5% (Peroxyl, own-label) is most useful as a short-term aid for aphthous ulceration and as a denture-cleaning rinse.

Indications:

• Recurrent minor aphthous ulcers (3% solution diluted, or 1.5% rinse, used short-term)
• Acute necrotising ulcerative gingivitis (alongside metronidazole and dental review)
• Cleaning around dental implants

Counselling:

• Spit out, do not swallow
• May cause transient burning sensation
• Not for use as routine plaque control
• Avoid in children under 12

Essential-oil mouthwash

Listerine and equivalents (eucalyptol, thymol, menthol, methyl salicylate in alcohol) provide modest plaque reduction in the order of 6–10% versus brushing alone.

Counselling:

• Useful as an adjunct in motivated patients
• Alcohol-free formulations exist for patients on disulfiram, in recovery from alcohol dependence, or for children
• Not a substitute for brushing and interdental cleaning
• Heavy use may cause mucosal irritation in some patients

Mouthwashes for ulcer pain

Two over-the-counter formulations target ulcer pain rather than the cause:

• Benzydamine 0.15% (Difflam) — a topical NSAID. Useful for radiation mucositis, post-extraction soreness and aphthous ulcer pain. Maximum 7 days continuous use; may cause transient stinging and rarely numbness of the tongue.
• Lidocaine-containing mouthwashes — short-lived numbing for severe ulcer pain. Caution: numbness affects swallowing and increases the risk of biting the cheek or tongue. Maximum 4 hourly doses.

Saline mouthwash — the underused option

Warm saline (one teaspoon of salt in a glass of warm water) is the simplest post-extraction rinse, the recommended NHS first-line for sore throat in children where lozenges are unsuitable, and a low-cost adjunct for any post-procedure inflammation. It has no contraindications, no taste-masking issues, and no ingredient cost.

What mouthwash will not do

• Replace tooth-brushing with fluoride toothpaste
• Treat established periodontitis
• Treat dental abscess (antibiotic prescribing decision needed)
• Address halitosis without identifying the underlying cause (periodontal disease, dry mouth, nasal pathology, gastric reflux)
• Whiten teeth meaningfully — most "whitening" mouthwashes contain low-concentration peroxide insufficient for visible whitening

When to refer to a dentist

• Bleeding gums persisting more than two weeks
• Loose teeth in adults
• Mouth ulcer not healed after three weeks (urgent — head and neck cancer pathway)
• Persistent halitosis
• Dental pain that disturbs sleep
• Trismus (limited mouth opening) following infection or trauma

PharmSee's pharmacy directory shows community pharmacies offering oral-health consultations and signposting; the pharmacist career hub covers the wider role of the community pharmacist in minor oral conditions referred from NHS 111 and dental access. The PharmSee jobs board lists current pharmacy vacancies across the UK.

Sources

• BNF — Mouthwashes and dental gels
• Cochrane Review — Chlorhexidine mouthrinse for prevention and control of plaque and gingivitis (James 2017)
• Cochrane Review — Fluoride mouthrinses for preventing dental caries (Marinho 2016)
• Faculty of General Dental Practice — Antimicrobial Prescribing for General Dental Practitioners
• NICE Clinical Knowledge Summary: Aphthous ulcer