Boric acid suppositories, what they are used for and who should not use them

What boric acid is.

Boric acid is a mild acid made from boron. It is also sold as a household insecticide, which tells you why swallowing it is dangerous. For vaginal use it comes as a powder sealed in a capsule that dissolves inside the vagina. It works against the bacteria behind BV and against several types of yeast, including some that resist standard antifungals.

It is not a new idea. Clinicians have used it for decades. What has changed is that it is now sold over the counter, which is why it shows up in so many searches. The over the counter version is the same compound clinicians have prescribed. What you lose without a clinician is the diagnosis.

What the evidence says.

The evidence is real but narrow. Boric acid is good at a few specific jobs.

Use	What the evidence shows	Where it fits
Recurrent bacterial vaginosis	Included in CDC guidelines as part of a regimen for multiple recurrences	After a prescription antibiotic, under a clinician's plan
Non-albicans yeast (such as C. glabrata)	CDC cites eradication rates of about 70 percent	When standard azole antifungals fail
Recurrent or azole resistant yeast	2011 review of 14 studies, mycologic cure 40 to 100 percent	An alternative when conventional treatment fails
A first, undiagnosed odor or itch	No good evidence	See a clinician first
Trichomoniasis	Being studied; not a standard treatment	Needs prescription treatment

Recurrent BV. The CDC treatment guidelines describe a regimen for women with multiple recurrences: a course of a prescription antibiotic, then vaginal boric acid, then suppressive treatment. Boric acid is one piece of a plan, not the whole plan.

Stubborn yeast. Most yeast infections are caused by Candida albicans and clear with standard antifungal creams or tablets. A minority are caused by other species, such as Candida glabrata, which often resist those drugs. The CDC lists vaginal boric acid for these, with clinical and mycologic eradication rates of about 70 percent. A 2011 review in the Journal of Women's Health pooled 14 studies and concluded boric acid is a safe, economic alternative when conventional treatment fails.

What it is not. It is not a deodorant, a pH tune up, or a routine cleanse. Using it on a smell nobody has diagnosed can mean treating the wrong thing, and trichomoniasis, a common STI with a similar smell, needs prescription treatment.

How it is used.

In general terms: one capsule goes into the vagina, often at night, and it dissolves over several hours. Watery discharge is common, which is why pH-D suggests wearing a panty liner. How often and for how long depends on what is being treated, so follow the product's label and your clinician. Wash your hands before and after.

Who must not use it.

These are not fine print. They are the reason to read this section twice.

• Pregnancy. Guidelines recommend avoiding vaginal boric acid in pregnancy. A 2021 safety review found the data on harms in pregnancy limited, not reassuring enough to change that advice.
• Never by mouth. Boric acid is toxic if swallowed. Store it like a medicine, out of reach of children and pets. If someone swallows it, call Poison Control at 1-800-222-1222.
• Broken or irritated skin. Do not use it on sores, cuts or very inflamed tissue.
• Without a diagnosis, for the first time. Get a diagnosis before reaching for it.
• Oral sex during use. Skip oral sex while you are using boric acid. It is toxic if swallowed.

Side effects.

Studies report mild vaginal burning in fewer than 10 percent of users, watery discharge and some redness. The 2021 review in Sexually Transmitted Diseases concluded that, despite gaps, boric acid appears safe at the doses clinicians commonly prescribe. It also noted that boric acid is not an FDA approved drug and that safety data are sparse. Stop and call your clinician if burning is strong, you develop sores, or symptoms get worse.

If you buy it over the counter.

Pick a product sold specifically for vaginal use, with sealed capsules and clear instructions. Do not make your own from household boric acid. pH-D is the best known over the counter brand.

When to see a clinician.

See a clinician before your first use, and any time you have a new smell, discharge, itching or burning that has not been diagnosed. Go back if symptoms return after treatment, or if they come back more than a few times a year, since recurrent BV and recurrent yeast both have prescription options. Get care right away if you are pregnant and have symptoms, or if you have fever, pelvic pain or sores. This page is general information, not medical advice.