There are three main causes of vaginal infections: the fungus (yeast)
Candida albicans
, the parasite
Trichomonas vaginalis
, and the bacterial organism
Gardnerella vaginalis
.
Factors that can contribute to vaginal infections include antibiotics (which kill friendly bacteria, allowing yeast to grow), corticosteroids and HIV (which suppress the immune system),
oral contraceptives
and pregnancy (which alter the vaginal environment by changing hormone levels), and
diabetes
(increased sugar levels provide a friendly environment for yeast).
Conventional medical treatment for vaginal infections caused by
candida
include vaginal suppositories containing antifungal medications or, in some cases, oral antifungal medications. Women with diabetes often find that yeast infections are less common when their blood sugar levels are well controlled.
Proposed Natural Treatments
There are some promising natural treatments for vaginal infections caused by
candida
and other organisms, but the scientific evidence for them is not yet strong.
Probiotics
(friendly bacteria), such as acidophilus, are normally found in the vagina. When colonies of these organisms are present, it is difficult for unfriendly organisms, such as
candida,
to become established. Probiotic supplements can help restore a normal balance of vaginal organisms, which could, in theory, reduce the chance of developing a vaginal yeast infection.
24
For this reason, women who frequently experience yeast infections, or who are taking antibiotics, are often advised to consume probiotics. However, evidence that probiotics really help prevent vaginal yeast infections remains incomplete and inconsistent.
25-26
A fairly large study (278 participants) failed to find
Lactobacillus
helpful for preventing yeast infections caused by antibiotics.
26
Another kind of vaginal infection, called bacterial vaginosis, is most often caused
by Gardnerella vaginalis
. In a study120 women with a history of bacterial vaginosis, researchers found that vaginally inserting a daily capsule containing the probiotics
Lactobacillus rhamnosus
, acidophilus, and
Streptococcus thermophilus
did reduce recurrence.
33
While this study found benefit, other studies have produced mixed results regarding the benefits of probiotics in the treatment and prevention of bacterial vaginosis.
29-32
Tea tree oil
, an essential oil from the plant
Melaleuca alternifolia
, possesses antibacterial and antifungal properties
7
and appears to spare friendly bacteria in the
Lactobacillus
family.
8
Tea tree oil has been tried for various forms of vaginal infection, but again there is little scientific evidence as yet that it works. In an
open
trial, 96 women with
trichomonal vaginitis
were treated with tampons saturated in tea tree oil, which were left in the vagina for 24 hours, and then followed by daily vaginal douches with a tea tree oil solution.
9
The researcher reported good results with this regimen in 3 to 4 weeks. However, because this was not a double-blind trial, the results mean little. (For information on why double-blind studies are so important, see
Why Does This Database Rely on Double-blind Studies?
)
A double-blind study of 100 women found vitamin C vaginal tablets (250 mg) at most marginally helpful for nonspecific vaginitis.
28
Boric acid is a chemical substance with antiseptic properties. A double-blind comparison study of 108 women with yeast infections found that 92% of those who used boric acid suppositories nightly for 2 weeks experienced full recovery, as compared to 64% of those given suppositories of the somewhat outdated antifungal drug nystatin.
11
However, there are safety concerns with boric acid. If taken internally, it is quite toxic. For this reason, it should not be applied to open wounds. In addition, it should not be used by pregnant women, nor be applied to the skin of infants.
13
A
single-blind
trial, involving 100 women with
candida
vaginitis
, compared nystatin suppositories against suppositories made from the plant
Solanum nigrescens
and found equivalent benefits.
14
However, this plant can be toxic and should not be used except under physician supervision.
Test tube studies have found antifungal properties in numerous herbs, including the tropical tree
Tabebuia avellanedae
,
16garlic
extracts,
17-19
the plant alkaloid berberine sulfate (found in
goldenseal
),
20
and
essential oils
of various plants, including
cinnamon
, eucalyptus, lemongrass, oregano, palmarosa, and
peppermint
.
21-23
However, it is a long way from
test tube
studies to proof of safety and effectiveness in people.