1 Diluted boric acid is commonly used as a suppository inserted in the vagina to treat yeast infection . 2 Several commercial douching products contain boric acid. Boric acid also has antiviral activity. Topical diluted boric acid ointment in the form of sodium borate has been used to shorten the outbreak of cold sores in a double-blind trial. 3 Duration of cold sores was approximately four days with boric acid but six days with placebo.
Boric acid is available in powder form from a pharmacy without a prescription.
This powder is packed tightly into empty gelatin capsules and used as a suppository. For women with vaginitis , some doctors recommend one such capsule be inserted into the vagina each night for two weeks. Some health food stores have prepared suppositories of a combination of boric acid and herbs. Because of the potential toxicity, people should consult their doctors before using boric acid. Suppository boric acid capsules should not be used during pregnancy .