What causes a yeats infection?
A fungus combined with moisture and a lack of good bacteria to fight it. Some people will get them while on antibiotics because they kill they good bacteria as well as the bad. I just eat yogurt when on antibiotics and avoid that.
Gatorblu's answer is very good. A surgeon told me to eat a small container of yogurt every day, and it will keep off yeast infections in many areas of the body.