Can grapefruit juice cause yeast infections in women?

No: I have not found any evidence that drinking grapefruit juice (or eating grapefruit) will cause a yeast infection. Yeast infections are caused by yeast. While you have yeast all the time, it's usually in balance w/everything else living there. However, antibiotics can cause yeast infections by upsetting balance btwn yeast & bacteria, thus changing from colonization to infection http://goo.gl/Ch99Er