Dementia is a group of symptoms, characterized by a loss of cognition that interferes with everyday tasks, difficulty focusing, planning, problem solving, and behavioral changes, such as apathy, anxiety, or depression. The leading cause of dementia is Alzheimer’s disease, but vascular dementia or mild cognitive impairment are also frequently occurring. There are six drugs legislated in Europe for use in the treatment of dementia. There are unmet clinical needs to find more effective, better tolerated or complementary therapeutic options. The aim of this study is to comprehensively analyze the results of clinical trials and other human studies regarding the efficacy and safety of herbal interventions used in patients with dementia.

We enrolled a total of 48 studies for this systematic review, of which 27 were included into the statistical analysis of effect size (Cohen’s d).

We found significant improvements mainly after administration of Ginkgo biloba, Crocus sativus, Salvia officinalis, and Melissa officinalis.It should be emphasized that some herbs and herbal formulations demonstrated efficacy comparable to that of donepezil, a widely used and approved medication, suggesting potential for phytopharmaceutical therapies as complementary approaches. In some studies, the observed effects were similar to those reported for conventional treatments, indicating promising directions for further research in Alzheimer’s disease and dementia.

In light of the evidence, phytopharmaceuticals have a promising role as a co-therapeutic option or alternative for patients with dementia who do not tolerate or have contraindications to standard medications. However, further research is necessary to translate these initial promising results into clinical practice.

Phytopharmaceuticals have a promising role as a complementary or alternative option for dementia patients who cannot tolerate or respond to standard medications. Certain phytopharmaceuticals demonstrated comparable short-term symptomatic effects to standard treatments in small trials; however, evidence is insufficient to support equivalence or superiority.

Many of the studies reviewed are limited by very small sample sizes, which is associated with a high risk of bias when interpreting large effect sizes (Cohen’s d). The short duration of interventions (often only 3 to 6 months) is insufficient to assess whether phytotherapeutics can constitute disease-modifying treatments (DMTs).