Post-stroke depression (PSD) is the most frequent psychiatric illness in stroke survivors [1,2], with nearly half of stroke patients suffering from PSD [3]. It is underdiagnosed and undertreated, and may increase mortality and hospital stays, inhibit functional recovery, and reduce quality of life and engagement in meaningful careers [[4], [5], [6]]. Therefore, the clinical diagnosis and treatment of PSD symptoms are considered essential priorities for healthcare providers.

Increasing evidence suggests that sleep disorders are strongly associated with the onset, progression and recurrence of depression [7,8]. Improvements in sleep quality can reduce mood instability and enhance self-regulation in depressed patients [9]. Currently, the first-line medications for PSD, such as fluoxetine, paroxetine, sertraline, and citalopram, are effective in improving sleep quality and alleviating depressive symptoms, but they have serious side effects and are expensive [10,11]. Therefore, non-pharmacological therapies have been suggested to manage these problems.

Inhalation aromatherapy, a method of inhaling essential oils, has become an increasingly popular non-pharmacological therapy in recent years due to its few complications, easy accessibility, and ability to treat a variety of physical and emotional problems [[12], [13], [14]]. Lavender essential oil is a broadly used fragrance oil in aromatherapy. Its properties include sedative, antidepressant, antispasmodic, antiseptic, and local anesthetic effects. It is also used to relieve migraines and insomnia [15,16]. Recent studies have proved the effectiveness of inhaling lavender essential oil on improving depression symptoms in hemodialysis patients [17], older community-dwelling people [18], and women of childbearing age [19]. In addition, inhalation aromatherapy with lavender essential oil has also shown ideal results in reducing stress, anxiety, and pain, as well as improving the vital signs in children with burns [[20], [21], [22]].

Although recent evidence suggests that lavender essential oil has positive effects in the treatment of various physiological and psychological disorders, the potential benefits of lavender aromatherapy in reducing depression in patients with PSD remain less clear, and further research and experiments are needed. Therefore, this trial intended to explore the impact of inhalation aromatherapy with lavender essential oil on depression and sleep quality in patients with PSD. We hypothesized that patients undergoing lavender essential oil inhalation aromatherapy would experience a noticeable improvement in depression compared to those undergoing placebo treatment.