The non-profit Center for Science in the Public Interest (CSPI), Washington, D.C. has called on FDA to require a warning label on dietary supplements containing St. John’s Wort, saying these products may interfere with birth control, antidepressants, blood thinners and other prescription and over-the-counter drugs.

St. John’s Wort is a flowering plant often promoted for its supposed antidepressant properties. But CSPI said that individuals who take it with prescription antidepressants might unwittingly be counteracting the very treatment they are seeking. Similarly, women taking St. John’s Wort and oral contraceptives may have unplanned pregnancies.