Ironically, I was researching this yesterday. I used to get yeast infections chronically. However, I haven't had on in over a year, but started feeling some symptoms late last week. I looked at what I had been doing differently and then researched it. I think one reason I got one is because I stopped eating yogurt for a week. Another reason is that I took some Codiene(sp) which may have been mixed with an antibiotic.
Upon research yogurt can be a great preventitive measure. There was a case in 1974 (I believe) where a woman was prescribing yogurt inserts to women who had yeast infections. While I'm not sure I would insert yogurt inside me, some say that it really works. Another thing that help is sleeping without panties on and drinking cranberry juice. I started eating yogurt again, drank some cranberry juice, and slept without panties on. Symptoms are almost cleared up.
I'm not sure about a pill and I'm not a big fan on medicine. I believe that the body can become immuned ot something that is taken regularly. Looks like snowy did some good research for you though.
Good luck! I think that yeast infections and urinary tract infections are the worst possilble things to have. And I have had more than my share.