What is Boric Acid?

Boric acid is a salt of the element Boron, and it has many surprising uses--from fertilizer or a pool additive to a treatment for certain vaginal infections. These three connections are all because boric acid has antiviral, antifungal, and antibacterial properties.

You might notice that boric acid’s name is similar to the popular cleaning agent Borax, but rest assured, these are not the same (though they do both come from Boron).

What is Boric Acid Used For?

In addition to the uses above (and several other manufacturing and household uses), boric acid can be used to treat a number of infections that cause vaginitis, a group of vaginal conditions that cause irritation and/or inflammation of the vagina.

Boric acid has been shown to cure 72% of yeast infections within 30 days (Van Slyke, Michel, & Rein, 1981), and has also been shown to treat chronic yeast infections with longer use (Iavazzo et al, 2011).

It can also treat another vaginal infection caused by the torulopsis glabrata pathogen (Sobel & Chaim, 1997), as well as the sexually transmitted infection trichomoniasis (“trich”) (Brittingham & Wilson, 2014).

It is possible that boric acid can treat bacterial vaginosis (Mullins & Trouton, 2015) or other sexually transmitted infections, but more research is needed.

How to Use Boric Acid

When you purchase boric acid suppositories, they will look like a capsule pill and you may think this means you take them orally. This is not the case! You should never ingest a boric acid capsule by mouth.

The capsules are meant to be inserted into the vagina, sometimes with a plastic applicator.

Here is how you use it:

  1. Wash and thoroughly dry your hands before coming into contact with your vagina.
  2. Get out your applicator (if it comes with one) and be ready to insert the boric acid capsule into your vagina quickly. You do not want to handle the boric acid capsule for too long or the capsule may begin to melt in your hands.
  3. Insert the capsule as far into the vagina as you can, with either your fingers or the applicator.
  4. Wash your hands after application.

Is Boric Acid Safe?

Boric acid is generally safe when taken correctly, i.e. not taken by mouth. If you were to take a boric acid tablet by mouth, it would not treat your vaginal infection, but it would give you some unpleasant gastrointestinal side effects like nausea, diarrhea, a stomach ache, and vomiting (Boone, Bond, & Stone, 2012).

When taken vaginally, the following side effects may occur, especially if the capsule is not inserted far enough into the vagina:

  • Burning sensation
  • Watery discharge
  • Erythema (reddening of the skin)

In one study, 4% of the 92 patients reported one or more of these side effects, and none were considered serious (Jovanovic, Congema, & Nguyen, 1991).

Because of the potential for watery discharge, you may want to wear a panty liner while using boric acid suppositories.

Boric acid capsules are safe to use while on your period, but you should not use a tampon within 24-48 hours of using boric acid; use a menstrual pad instead.

You should also refrain from engaging in sex until 24-48 hours after your last boric acid treatment. In cases where penile-vaginal sex has occurred shortly after boric acid treatment, partners have reported pain in their penis or pelvis--known as male dyspareunia (Jovanovic, Congema, & Nguyen, 1991)--or a gritty sensation during sex.


When taken properly, boric acid is a safe and highly affordable treatment for many vaginal conditions--even chronic ones. Don’t let the fact that boric acid looks like a pill capsule confuse you--boric acid capsules are meant to be inserted into the vagina, not taken orally.

And as a general rule, you should wait 24-48 hours after boric acid treatment before putting anything else in your vagina (such as a penis, tampon, or sex toy).

If you have any further questions, or would like to explore whether boric acid is right for your short- or long-term vaginal condition, talk to your doctor.


  1. Van Slyke, K. K., Michel, V. P., & Rein, M. F. (1981). Treatment of vulvovaginal candidiasis with boric acid powder. American journal of obstetrics and gynecology, 141(2), 145-148. https://doi.org/10.1016/S0002-9378(16)32581-9
  2. Iavazzo, C., Gkegkes, I. D., Zarkada, I. M., & Falagas, M. E. (2011). Boric acid for recurrent vulvovaginal candidiasis: the clinical evidence. Journal of Women's Health, 20(8), 1245-1255. https://doi.org/10.1089/jwh.2010.2708
  3. Sobel, J. D., & Chaim, W. (1997). Treatment of Torulopsis glabrata vaginitis: retrospective review of boric acid therapy. Clinical infectious diseases, 24(4), 649-652. https://doi.org/10.1093/clind/24.4.649
  4. Brittingham, A., & Wilson, W. A. (2014). The antimicrobial effect of boric acid on Trichomonas vaginalis. Sexually transmitted diseases, 41(12), 718-722. https://doi.org/10.1097/OLQ.0000000000000203
  5. Mullins, M. Z., & Trouton, K. M. (2015). BASIC study: is intravaginal boric acid non-inferior to metronidazole in symptomatic bacterial vaginosis? Study protocol for a randomized controlled trial. Trials, 16(1), 1-7. https://doi.org/10.1186/s13063-015-0852-5
  6. Boone, C.; Bond, C.; Stone, D. (2012). Boric Acid General Fact Sheet; National Pesticide Information Center, Oregon State University Extension Services. http://npic.orst.edu/factsheets/boricgen.html.
  7. Jovanovic, R., Congema, E., & Nguyen, H. T. (1991). Antifungal agents vs. boric acid for treating chronic mycotic vulvovaginitis. The Journal of reproductive medicine, 36(8), 593-597. https://europepmc.org/article/med/1941801
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