First, make simple changes: Take showers rather than baths, and wear only cotton underwear, for instance.
If that doesn't work, "make sure it's really yeast," says Steven Sondheimer, M.D., professor of obstetrics and gynecology at the University of Pennsylvania. A visit to your doctor might reveal that you really have bacterial vaginosis, an STD (like trichomoniasis or chlamydia), or an allergic reaction to a product. Once these are ruled out, work with your doctor to find what will restore your body's balance. Some options:
Get tested for diabetes. High blood-sugar levels give yeast something to thrive on. If yours are elevated, a diet and exercise program can be effective. Even if your blood-sugar levels are normal, curbing your sweet tooth might be a help anyway.
Consider your period. Hormonal fluctuations right before menstruation are a common trigger. Sometimes, a birth-control switch can help; the NuvaRing's slow release of estrogen and progesterone, for example, may increase the "good" bacteria in the vagina, crowding out the bad.
Try different medications. Possibilities include: Terazol, a suppository and/or cream that's stronger than over-the-counter options; an ongoing weekly course of an antifungal (such as Diflucan) to prevent recurrence; or treatment with boric-acid suppositories to maintain your body's pH balance.
What won't work: Oft-recommended dietary measures like eating more yogurt, taking acidophilus pills, or eliminating foods with yeast.