I've had a yeast infection for 4 weeks. i did the 7-day monistat treatment twice and took prescription medicine. all three times the symptoms returned?

Confirm diagnosis: If a yeast infection is not responding to treatment, the first step is to confirm the diagnosis. Your primary physician will ensure that you are treating the right infection, prescribe alternate medication if your have an infection that is resistant to miconazole and check for any serious illness such as Diabetes or HIV infection. Such illness often reduce ones ability to fight common infections.

Vaginal Candidiasis: Sounds like your OTC treatment for vaginal candidiasis (i.e., yeast infection) has NOT been effective. You will need to present to your PCP or OB/Gyn for a full evaluation (i.e., history & physical w/ pelvic exam) to determine the exact nature of your symptoms and Rx the appropriate medication. This may or may not incl. the anti-fungal medication Diflucan (fluconazole) if candidiasis is confirmed.