The live culture in plain yogurt is a great remedy for a yeast infection, helping to restore the acid-bacteria balance in more ways than one. Of course, you can eat yogurt. But you can also insert 1 to 2 tablespoons into your vagina, apply it externally to the affected area (anal or vaginal), or use it as a douche by diluting it with warm water.
Another alternative is to use lactobacillus tablets vaginally once or twice a day and douching with vinegar twice a day for two days. Check the natural-supplement aisle of your local pharmacy or a health-food store for the lactobacillus tablets.