Yes!, St. John's Wort is at this time, the only herb that's being advised against if you're on b.c. There have been pregnancies due to it's interaction (weakening of) with the pill (or patch or shot). Its warning is now on b.c. printouts you should get with your meds. Of course, it doesn't mean it's going to happen to everyone- but I wouldn't take chances- take a pg test. Good Luck!