I've been using an infusion of apple cider vinegar with lavender, peppermint and chamomile. I created this infusion to use on my hair and scalp, but I started using it all over...
I started with a small jar and infused:
1/3 cup chamomile
1/3 cup lavender
1/3 cup peppermint
2 to 2 1/2 cups of apple cider vinegar (I use Great Value brand)
Steep for 2-3 weeks in dark place, turn or shake occaissionally and strain herbs out. This doesn't spoil (as far as I can tell), so I store it in an old shampoo bottle in the bathroom. This infusion seemed a bit strong, so I actually added 2-3 more cups of vinegar to the infusion after I strained it, but you can leave it this strong if you prefer the extra effects of the herbs. Then I take another empty shampoo bottle and mark it with 1-3 Tablespoon marks. Fill the empty marked bottle to the line of preference (I usually use 3 but I have very long hair) and then fill the rest of the bottle with warm water (about 3 cups).
After much experimentation and research, I've found the qualities in these herbs are very beneficial for many things on your hair, skin and scalp, so I use it all over, especially on my head, body hair and under my arms. This deoderizes, regulates pH, and it promotes hair growth and is also antimicrobial as well as aromatheraputic (even though the vinegar isn't pleasant smelling, the other herbs can still do their thing through absorbtion and inhalation).
I've also used this as a douch using equal parts vinegar rinse and water during yeast infections and had very good results. I did however use this in conjunction with other treatments, so I'm not sure if this would kill the yeast alone, but it definately helps with the irritation and itching.
For a quick fix you can make a tea on the stove. Boil 2-3 cups of water, turn off water and add 2 T cider vinegar and 1/3 tsp each of chamomile, lavender and peppermint. Cover and allow to steep for 15-30 minutes.
This recipe is good if you're out of infusion or if you're in a hurry, but I recommend the time infusion as it's much stronger so you have less waste with your expensive herbs.
NOTE: Purified, distilled or rain water is going to work better because it's softer, BUT I always use tap water. The vinegar rinse works well enough, that I find the hardness of my water is no longer a factor.