St. John's wort - From MedlinePlus, a service of the U.S. National Library of Medicine
The page discusses interactions with various medications and supplements.
I have never used St. John's wort and so cannot speak from personal experience.
Also:
St. John's Wort for Depression by PsychCentral Staff
__________________
My dog
mastered the "fetch" command. He would communicate he wanted something, and I would fetch it.