According to dermatologist Amy Wechsler, the most common cause of dandruff is an overgrowth of a yeast called Pityrosporum ovale, though bacteria can also be a culprit. The result is dead skin cells that accumulate on the scalp, flake off and itch. Apple cider vinegar is an effective fungicide and germ killer, making an apple cider vinegar dandruff treatment a natural, affordable alternative to commercial dandruff products.

Besides the apple cider vinegar, you'll only need a few varieties of dried herbs. Common choices are thyme, rosemary and sage. Using an herbal vinegar dandruff treatment is a practical use for the last few tablespoonfuls of dried herbs that have been in your cabinet for six months or so and need replacing.

Gather 1/4 cup of dried herbs in any combination you like. You could also use 1/4 cup of a single type of dried herb if you wish. You can bundle the herbs in a square of cheesecloth to make a sachet or you can leave them loose.

Bring two cups of apple cider vinegar just to a boil. Remove it from the heat and add the herbs or herb sachet. Let the mixture steep anywhere from one hour to overnight. Strain the mixture and pour the liquid into an empty, labeled jar or bottle.

Dilute the mixture before you apply it--1/8 cup of the vinegar treatment in one cup of water is a strong enough solution. Douse your hair and scalp with the solution before you shampoo and after you condition. Don't rinse out the second application, though. Just squeeze out the excess and dry your hair as usual.

You can steep the herbs in the vinegar at room temperature to avoid boiling the vinegar. This is most effective if you leave them to steep for eight hours or more. Also, you could dab undiluted apple cider vinegar directly on your scalp with a cotton ball before shampooing instead of using the pre-shampoo vinegar treatment rinse. Wrap a towel around your head and let the vinegar work for an hour before you shampoo.

The dandruff flakes will be noticeably fewer after the first treatment and should clear up completely in a week or two. For more advanced dandruff, though, it may take up to a month. As a bonus, the vinegar in the post-conditioner rinses will leave your hair shinier.

Apple cider vinegar fumes are strong and can sting your eyes, especially if you use the dandruff treatment in the shower. Be sure to have adequate ventilation in the bathroom or kitchen as you work with the vinegar.

If you don't see your dandruff improving after four weeks of using vinegar treatments, see your doctor or dermatologist.