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Boric Acid


Boric acid is a chemical substance with mild antiseptic, antifungal, and antiviral properties.

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Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.

2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for Why
2 Stars
Yeast Infection
Insert vaginal suppositories containing 600 mg twice per day
Boric acid capsules inserted in the vagina have been used successfully as a treatment for vaginal yeast infections.

Boric acid capsules inserted in the vagina have been used successfully as a treatment for vaginal yeast infections. One study demonstrated that 85% of women who used boric acid vaginal suppositories were cured of chronic recurring yeast vaginitis.1 These women had all previously failed to respond to treatment with conventional antifungal medicines. The suppositories, which contained 600 mg of boric acid, were inserted vaginally twice a day for two weeks, then continued for an additional two weeks if necessary. Boric acid should never be swallowed.

1 Star
Cold Sores
Refer to label instructions
Boric acid has antiviral activity and has been shown to shorten the duration of cold sores.

Boric acid has antiviral activity. In a double-blind trial, topical application of an ointment containing boric acid (in the form of sodium borate) shortened the duration of cold sores by about one-third.2 However, concerns about potential toxicity have led some doctors to avoid the use of boric acid for this purpose.

How It Works

How to Use It

Boric acid is available in powder form from a pharmacy, without a prescription. This powder can be packed into an empty gelatin capsule and used as a suppository. For women with vaginitis, some doctors recommend that one such capsule, containing 600 mg of boric acid, be inserted into the vagina each night for two weeks. Some health food stores have suppositories that contain a combination of boric acid and herbs.

In the trial studying cold sores, an ointment diluted to 4% boric acid was applied four times per day. Because of the potential toxicity of such a preparation, people should consult their doctors before using boric acid.

Where to Find It

Boric acid is a white, odorless powder or crystalline substance that is available in many over-the-counter pharmaceutical products for topical use, alone as a topical antiseptic, and in suppository form.

Possible Deficiencies

Boric acid is not taken internally and is not a nutrient; no deficiency exists.


Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Interactions with Medicines

As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Side Effects

Boric acid suppositories should not be used during pregnancy. Boric acid is very toxic when taken internally and should also never be used on open wounds. When boric acid enters the body, it can cause nausea, vomiting, diarrhea, dermatitis, kidney damage, acute failure of the circulatory system, and even death. In the past, boric acid was used as a topical treatment for infants with diaper rash. However, even in diluted (3%) form it caused significant toxicity and two deaths.3 Therefore, boric acid should not be applied to the skin of infants and small children. In fact, experts in the field have stated, “The minor therapeutic value of this compound, in comparison with its potential as a poison, has led to the general recommendation that it no longer be used as a therapeutic agent.”4 However, in more recent research, no serious side effects were reported when boric acid was used as a treatment for vaginitis.


1. Jovanovic R, Congema E, Nguyen HT. Antifungal agents vs. boric acid for treating chronic mycotic vulvovaginitis. J Reprod Med 1977;36:593-7.

2. Skinner GRB, Hartley CE, Millar D, Bishop E. Possible treatment for cold sores. Br Med J 1979;2:704.

3. Penna RP, Corrigan LL, Welsh J, et al. Handbook of Nonprescription Drugs, 6th ed. Washington, DC: American Pharmaceutical Association, 1979, 424 [review].

4. Penna RP, Corrigan LL, Welsh J, et al. Handbook of Nonprescription Drugs, 6th ed. Washington, DC: American Pharmaceutical Association, 1979, 424 [review].

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