St. John's Wort and Reduced Depression Symptoms

Research synthesisLow evidenceMixed effect size3 studies · 3 beneficial · 0 neutral · 0 harmful

Across 3 studies, all reported beneficial effects of St. John's Wort on reducing depression symptoms, with effect sizes ranging from small to moderate. The available evidence is preliminary due to the small number of studies, and no consistent dose, duration, or population data were extracted.

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Two of the three studies are reviews without specifying doses, durations, or sample sizes, limiting the strength of the synthesis.

Generated May 16, 2026

Safety in these studies

Overall tolerabilityReportedSerious adverse event
St. John's wort is effective in alleviating mild to moderate depression; however, careful use is necessary particularly due to possible interactions with other drugs.
from: Medicinal Plants Used for Anxiety, Depression, or Stress Treatment: An Update.
Overall tolerabilityReported
They show good effectiveness in human studies and alleviate the symptoms of depression.
from: Phytochemicals in the treatment of patients with depression: a systemic review.

3 of 3 papersPopulation:

Phytochemicals in the treatment of patients with depression: a systemic review.
- 2024-12-09
- Systematic Review
- Frontiers in psychiatry 15
- - Natalia Picheta
  - Julia Piekarz
  - Karolina Daniłowska
  - Karol Mazur
  - Halina Piecewicz-Szczęsna
  - Agata Smoleń
- PubMed: 39717381
- DOI: 10.3389/fpsyt.2024.1509109
3 Insights on
- Reduced Depression Symptoms
- High evidence
In the treatment of depression, plants such as Crocus sativus L. stigma, Lavandula angustifolia, Hypericum perforatum L. and Curcuma longa L. have proven to be effective. They show good effectiveness in human studies and alleviate the symptoms of depression.
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Medicinal Plants for Child Mental Health: Clinical Insights, Active Compounds, and Perspectives for Rational Use.
- 2025-08-28
- Review
- Children (Basel, Switzerland) 12(9)
- - Giovanna Rigillo
  - Joan M C Blom
  - Arianna Cocchi
  - Valentina Martinucci
  - Francesca Favaro
  - Giulia Baini
  - Giorgio Cappellucci
  - Fabio Tascedda
  - Marco Biagi
- PubMed: 41007011
- DOI: 10.3390/children12091142
6 Insights on
- Reduced Depression Symptoms
- Low evidence
- Children
Herbal products showing clinical promise include Bacopa monnieri (L.) Wettst., Crocus sativus L., Ginkgo biloba L., Hypericum perforatum L., Lavandula angustifolia Mill., Melissa officinalis L., Panax ginseng C.A. Meyer, Passiflora incarnata L., Pinus pinaster Aiton, Valeriana officinalis L., and Withania somnifera (L.) Dunal.
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Medicinal Plants Used for Anxiety, Depression, or Stress Treatment: An Update.
- 2022-09-15
- Review
- Molecules (Basel, Switzerland) 27(18)
- - Maša Kenda
  - Nina Kočevar Glavač
  - Milan Nagy
  - Marija Sollner Dolenc
- PubMed: 36144755
- DOI: 10.3390/molecules27186021
3 Insights on
- Reduced Depression Symptoms
- Low evidence
St. John's wort is effective in alleviating mild to moderate depression
Effect
Beneficial
Effect size
Small
Significant
Yes

St. John's Wort and Reduced Depression Symptoms

Phytochemicals in the treatment of patients with depression: a systemic review.

Medicinal Plants for Child Mental Health: Clinical Insights, Active Compounds, and Perspectives for Rational Use.

Medicinal Plants Used for Anxiety, Depression, or Stress Treatment: An Update.