St John's Wort

Our rating
2 smilies: This treatment is useful. It is supported by scientific evidence as effective, but the evidence is not as strong.


The rating system

  • 3 smiliesThese treatments are very useful. They are strongly supported as effective by scientific evidence.
  • 2 smiliesThese treatments are useful. They are supported by scientific evidence as effective, but the evidence is not as strong.
  • 1 smileyThese treatments are promising and may be useful. They have some evidence to support them, but more evidence is needed to be sure they work.
  • No smiley On the available evidence, these treatments do not seem to be effective.
  • Question markThese treatments have not been properly researched. It is not possible to say whether they are useful or not.
  • Exclamation MarkSafety or other concerns have been raised for the use of these treatments.

What is it?

St John's Wort (scientific name: Hypericum perforatum) is a small plant with a yellow flower that grows wild in Australia and many parts of the world. It is a traditional herbal remedy in Europe, but has only recently been studied scientifically as a treatment option for depression.

How does it work?

The way St John's wort works to help depression is not fully understood. However, it is thought to increase the level of chemical messengers (neurotransmitters) in the brain that are thought be in low supply in depressed people.

Is it effective?

There have been many studies comparing the effectiveness of St John’s Wort with placebos (dummy pills) and standard antidepressant medication. A systematic review of these studies has shown that St John’s wort works about as well as antidepressant medication for people with mild to moderate depression. It is also found that St John’s Wort had fewer side effects than antidepressants.

St John’s Wort may not be as effective as antidepressant medication for people with more severe depression.

Are there any disadvantages?

Like all medications, St John's Wort can have side effects – these may include insomnia, agitation and sleep problems. However, people taking St John’s Wort generally experience fewer side effects compared to those taking standard antidepressant medication.  

It is important to know that St John's Wort can interact with a number of other medicines. It can reduce the effects of these medicines, or increase their effects once St John's Wort is stopped. St John's Wort should not be taken in combination with any medication prescribed by your doctor for depression. If you are taking any other medication, whether it is for depression or any other condition, check with your doctor or a pharmacist before taking St John’s Wort.

Where do you get it?

St John's Wort is sold in tablet form at health food shops, pharmacies and many supermarkets. St John's Wort is also sometimes added to food products (such as herbal tea or breakfast cereal), but there is no evidence that it is effective in this form.


If you do not want to use an antidepressant drug prescribed by a doctor, and you do not have severe depression, St John's wort might be a useful alternative.

Key references

  • Carpenter DJ. St. John's wort and S-adenosyl methionine as "natural" alternatives to conventional antidepressants in the era of the suicidality boxed warning: what is the evidence for clinically relevant benefit? Altern Med Rev. 2011 Mar; 16(1):17-39.
  • Linde K, Berner MM, Kriston L. St John's wort for major depression. Cochrane Database of Systematic Reviews. 2008(4).
  • Ng QX, Venkatanarayanan N, Ho CY. Clinical use of Hypericum perforatum (St John's wort) in depression: A meta-analysis. J Affect Disord. 2017; 210:211-21.

Last reviewed and updated: 27 November 2023