Kank-A

Kank-A is an American brand of liquid pharmaceutical product marketed by Blistex used primarily to treat canker sores.[1] It is applied directly on the sore and works by numbing the local area (with benzocaine) to prevent discomfort and forming a protective mucous barrier with a compound benzoin tincture that protects the ulcer from further irritation, allowing it to heal more rapidly.

As of 2014, Kank-A comes in two varieties, the original providing oral pain relief against canker sores, and a soft gel that provides oral pain relief of toothaches.[2]