The effect of lavender aroma for anxiety disorder: a study protocol for a multicenter, double-masked, randomized, placebo-controlled clinical trial

BACKGROUND: Anxiety disorder is the most prevalent psychiatric disorder. Benzodiazepines, which are often used for anxiety in patients with anxiety disorder, have various side effects. Lavender, one of the most commonly used essential oils in aromatherapy, has the potential to reduce benzodiazepine use for anxiety disorders. METHODS: This study is a multicenter, double-masked, randomized, placebo-controlled clinical trial. The study will recruit patients aged 20–59 years old with generalized anxiety disorder and panic disorder among anxiety disorders. The bottle containing the test solution (lavender aroma essential oil or distilled water) will be given to the patients. Patients will carry the bottles with them in their daily life and use the drops on tissue paper when anxious. The primary endpoint is the number of times anxiolytics used in 28 days. DISCUSSION: If the use of benzodiazepines could be reduced by sniffing lavender aroma, which is inexpensive and safe, it would contribute not only to the risks associated with benzodiazepine use but also to the health care economy and could even be added as a standard treatment. TRIAL REGISTRATION: University hospital Medical Information Network Clinical Trials Registry (UMIN-CTR), ID: UMIN000034422 Registered 17 January 2019. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12906-023-04231-1.