Dry mouth symptoms mostly occur as drug side-effects. Available products such as saliva substitutes are disappointing (bad taste, poor efficiency).

The hypothesis stems from the "empirical" observations that many patients alleviate dry mouth symptoms by the consumption of dairy products. Through its composition, the dairy product in itself provides relief for the patient, due both to its physical and biochemical properties, which could explain these observed improvements, and to elements related to the phenomena of consumption of food as an alternative to medication. In the latter case, hedonism takes on a role which has not been previously assessed. Initial work undertaken with the department of applied research at the National Dairy Industry School (ENIL) led to the prototyping of a new milk product, to qualify and adapt a product with a "health benefit" in patients suffering from xerostomia.

This dairy product has specific taste, texture and lubrication properties and will be tested in a randomized controlled cross-over study for its efficiency and acceptability versus a reference product (Aequasyal ®, Oxidized Glycerol Triester) on a group of 32 patients at Dijon and at Besançon University Hospitals.

This way of combatting xerostomia at the interface of patients' diet, such as it is proposed here, could help improve their quality of life, minimize harmful effects (infection, decay) and promote adherence to treatments which are responsible for xerostomia.

Inclusion Criteria:

• Patients over 18 years old
• Patients seen in the psychiatry department requiring the prescription of psychotropic drugs (antidepressants anxiolytics) for over 6 weeks
• Patients complaining of xerostomia
• Patients having not taken a palliative therapy against xerostomia for at least 2 weeks
• Patients having signed a free and informed consent form
• Patients affiliated to a social security system

Exclusion Criteria:

• Patients suffering from psychotic illness
• Patients suffering from Sjogren's syndrome
• Patients having been treated by radiation therapy for head or neck cancer
• Patients having stopped a palliative therapy against xerostomia for less than 2 weeks
• Patients under 18
• Pregnant or Breastfeeding women
• Incapacitated adults
• Patients placed under tutorship or curatorship
• Patients under judicial protection
• Patients suffering from milk allergy or lactose intolerance