Benzocaine is a local anesthetic. It acts by blocking voltage-gated sodium ion channels in nerve endings. Benzocaine is available over-the counter for local anesthesia of oral and pharyngeal mucous membranes (sore throat, cold sores, mouth ulcers, toothache, sore gums, denture irritation), otic pain, and as a local anesthetic for surgical or diagnostic procedures. As a spray, benzocaine is used for temporary relief of pain and itching associated with minor burns, sunburn, minor cuts or scrapes, insect bites, or minor skin irritations. Topical application of benzocaine to gums or mouth may cause rare, but serious and potentially fatal adverse effect methemoglobinemia.