Many drugs, both prescription and OTC, can alter (increase or decrease) the metabolism of other drugs in which you are taking. For example, St. John's Wart contains the compound hyperforin. This compound increases the activity of a specific metabolizing enzyme(CYP3A4) that is responsible for the metabolism of some estrogenic compounds including the compounds in birth control pills. Thus, when you take St. John's Wart you will be decreasing the amount of estrogenic compounds necessary to prevent ovulation-meaning you will become pregnant!! Sorry for the lecture, this is just something for everyone to keep in mind when they are taking OTC drugs. I would recommend that you go the www.pubmed.com (http://www.pubmed.com) and research if any of the components will decrease the effectiveness of birth control pills.