The goal of this clinical trial is to learn if a new mouthwash can help soothing oral mucosa in adult patients with sensitive gums. The main questions it aims to answer are:

• Does the investigated mouthwash soothe red gum?
• Has the mouthwash antibacterial activities? Researchers will compare with a marketed mouthwash to see if the observed effect is due to the formula or to the general rinsing effect of any mouthwash.

Participants will be asked to use the investigated mouthwash or the comparative mouthwash twice a day for 21 days.

Severity of gingival inflammation is evaluated using the Loë & Silness scale, which includes 4 scores (0=no inflammation, 3=Significant inflammation, redness, accentuated hypertrophy with spontaneous hemorrhagic tendency and ulceration) by the dentist, on Day 0 and on Day 7.

Presence of dental plaque is evaluated using the Loë & Silness scale, which includes 4 scores (0=no dental plaque, 3=Abundant plaque along the gingival margin; the spaces between the teeth are filled with plaque) by the dentist, on Day 0 and on Day 7.

Changes in the gingival microbiota is evaluated through the analysis of bacteria on D0 and D7 by swab sampling on the occlusal and buccal surfaces at the gum line.

Tolerance (adverse effects) will also be studied by recording any adverse effect.

Inclusion Criteria:

• Person (man, woman) aged 18 or over,
• Person with a gingival index ≥ 2 (according to Loë & Silness) on at least 10% of teeth (i.e. 3 teeth) at the inclusion visit
• Person capable of following the instructions for using the product,
• Person agreeing to come for a dental consultation 7 days (+/- 1 day) after the inclusion visit,
• Volunteer informed and having signed their informed consent form,
• Volunteer person affiliated to a social security scheme (Art L1121-11 of the CSP).

Exclusion Criteria:

• Person who has regularly used mouthwash in the last month,
• Person suffering from periodontitis
• Person having a scaling treatment planned in the session, or having had a scaling treatment in the 6 months preceding the inclusion visit,
• Person having had antibiotic or antifungal treatment in the 3 months preceding the visit,
• Person taking anti-coagulant or anti-aggregant or immunosuppressive or anti-cancer treatment (chemotherapy or radiotherapy of the head and neck)
• Person at risk of infective endocarditis,
• Person with a known sensitivity or allergy to one of the components of mouthwashes, including components derived from essential oils (Eucalyptol, thymol, menthol, limonene).
• Volunteer participating in intervention research.
• Vulnerable people referred to in articles L. 1121-5 to 8 and L. 1122-1-2 of the Public Health Code (institutionalized volunteers, deprived of their liberty or placed under legal protection (guardianship or curatorship).