In any case, St. John's wort should not be mixed with other standard antidepressants because side effects may result. This is one reason why it is important to tell your doctor about all medications you are taking. Check with your doctor before taking St. John's wort or any other herb or medication. Your doctor can help you weigh the risks and benefits of a particular treatment so you can make informed health care decisions. The major components in extracts of St. John's wort include flavonoids, kaempferol, luteolin, biapigenin, hyperforin, polycyclic phenols, hypericin, and pseudohypericin.
Researchers believe the last three substances are the active ingredients.
5 New research suggests that hyperforin also may play a large role in the herb's antidepressant effects. Some German manufacturers of St. John's wort have begun standardizing, not only to hypericin as most U.S. manufacturers do, but to hyperforin as well. 13 Standardizing means that the manufacturer ensures that each individual supplement contains a uniform amount of a certain compound, in this case hypericin and hyperforin. Recent research suggests a possible application of St. John's wort for alcoholism. Researchers from the University of North Carolina at Chapel Hill found that St. John's wort reduced alcohol intake in laboratory animals.