Safety
St. John's Wort is the herb with the best evidence of efficacy in mild to moderate depression. This herb has been used for literally thousands of years to treat depression and may be a good starting point for patients looking for more natural medications.
Now that you have learned about St. John's Wort, continue to the next section to learn about SAMe.
There is a theoretical concern that the plant can acquire heavy metal toxins (e.g., lead, cadmium) through the soil it is grown in. Products using the whole plant rather than extracts are more likely to be contaminated.
The main precaution to take in using St. John's Wort is its ability to induce the cytochrome P450 enzyme CYP3A4. Precaution should be used especially with patients taking HIV drugs, hormonal contraceptives, antibiotics, immunsuppressants, and blood thinners. A complete listing of interactions can be found here.
(Frank Mayfield, Hypericum pyramidatum GREAT ST. JOHN'S WORT, flickr. CC: BY-SA 2.0. Obtained on June 21, 2009.)