Boric Acid: Indications, How to Use & Side Effects

Updated in December 2023

Boric acid is a substance with antiseptic, antifungal and astringent action. It can help to fight infections caused by bacteria or fungi, such as conjunctivitis, dermatitis and boils.

When combined with other substances, boric acid may be indicated to treat recurrent vaginal infections, such as bacterial vaginosis and recurrent yeast infections. Boric acid can also be used to make mouthwashes, make-up, nail polishes and soaps.

This substance is toxic however and is contraindicated in some situations. Therefore, boric acid should only be used under the guidance and supervision of a doctor.

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Common uses

Boric acid (particularly when in its boracic water form) is an astringent, antiseptic and fungicidal substance. It is used in medications that are indicated for the treatment of infections caused by bacteria or fungi, such as conjunctivitis, dermatitis and boils.

Furthermore, when used in combination with other medications, boric acid in the form of vaginal suppositories can also help to treat recurrent vaginal infections, such as recurrent bacterial vaginosis or recurrent yeast infections. It should only be taken or used as prescribed by your doctor.

How to use

Using boric acid varies according to the location of application and characteristics of the medication. The most common forms of boric acid are:

1. Boracic water

Boracic water is a solution that contains 3% boric acid. It is generally used by applying a few drops of the solution on a cotton ball or sterile gauze, and applying it to the skin in the area to be treated. It can also be applied to the eyes 2 to 3 times a day, as prescribed.

2. Boric acid vaginal ointment

For the treatment of bacterial vaginosis and yeast infections, boric acid (combined with other substances) can be found in the form of a vaginal ointment. This ointment is generally applied once a day for 7 to 10 days. You can also find it in powder form, which can be added to sitz bath preparations and used once or twice a day. 

3. Boric acid vaginal tablet

Boric acid vaginal tablets can be inserted vaginally at night before going to bed, for the duration established by your doctor. When treating an infection with a boric acid vaginal tablet, you should postpone sexual contact.

Possible side effects

Possible side effects of boric acid include vaginal burning, discharge or dryness, eye irritation, nausea, vomiting, abdominal cramps, blue/green diarrhea, hives, peeling skin, a drop in blood pressure and drowsiness.

Furthermore, boric acid in the form of vaginal suppositories can change your vaginal flora. This can increase your risk for other vaginal infections, especially when used incorrectly or for longer than recommended by the gynecologist.

Contraindications for use

Boric acid is not recommended for children. It cannot be applied to large areas of the body nor used topically on broken skin, such as open wounds, burns or cuts. It should not be ingested orally.

Furthermore, boric acid vaginal suppositories should not be used without medical advice, as it may cause an imbalance in vaginal flora. This can worsen recurrent infections or even increase the risk for other vaginal infections.

Boric acid vaginal suppositories should also not be used by pregnant women or women who have open wounds in the vagina.