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.