St. John's wort can be used for treating mild to moderate depression. Some research has shown the supplement to be as effective as several prescription antidepressants, but it may not be as effective in severe depression.  St. John's wort may also help with somatic pain disorder and in reducing menopausal symptoms such as hot flashes. *St. John's wort can interact with many medications, particularly if you take any prescription drugs, so always consult your practitioner before taking this herb.