St. John’s Wort (Hypericum perforatum) is a small plant with beautiful yellow flowers. It has a long history of human usage because of its mood-lifting effects. It’s used to release tension and stimulate a more positive outlook.


To make an infusion, pour a cup of boiling water onto 1-2 teaspoons of the dried herb and let it steep for 10-15 minutes. Do not take more than three cups a day.

For specific therapeutic purposes, it may be better to use this herb in the form of capsules or tablets containing a standardized extract.


St. John’s wort can negatively influence the effect of certain types of medication. St. John’s wort enhances the effect of the liver enzyme cytochrome P450. This causes some medicines to be broken down faster, making them less effective. When combining St. John’s wort with medication you are advised to consult your physician or your thrombosis prevention unit for information whether the combination can lead to such an interaction. This is the case not only if you want to start combining St. John’s wort, but also when you want to stop combining St. John’s wort with one of the types of medicine listed below:

  • immune system inhibitors, for instance against transplant rejections and auto-immune diseases: cyclosporine
  • anticoagulants of the coumarine type, such as acenocoumarol (Sintrom etc.) and phenprocoumon (Marcumar etc.)
  • Anticonvulsants: phenobarbital and phenytoine
  • bronchodilators: theophylline
  • cardiac glycosides for heart defects and heart rhythm disturbances: digoxin
  • HIV-virus inhibitors: indinavir

St. John’s wort can also influence the effect of SSRI-type antidepressants. Combining them is not recommended.

An incidental case of break through bleeding has been observed with the simultaneous use of St. John’s wort and certain types of the birth control pill (the combination of ethinyloestradiol and desogestrel, also known as sub-50). When a break through bleeding occurs, it may result in reduced protection against pregnancy.