Yeast infection is generally caused by the use of antibiotics. Avoid them and you will do much to prevent yeast infections.
Learn to treat infections with other methods.
There are a whole host of treatments for yeast infection. Of course the most common is over the counter medicaitons that work quickly for most people.
You can do a search on google for using boric acid, yogurt, gentian violet, colloidal silver, Lugol's iodine. My medical doctor often recommends colloidal silver administered with a 10cc syringe 3 times a day.
