Benzocaine is a local anesthetic drug. It is directly applied to the skin and used as a topical pain reliever or in cough drops. Benzocaine works by creating a chemical barrier that halts the build up of sodium, which accumulates as the nerve endings are stimulated by pain. When sodium builds up, electrical signals also build in the nerve ending and are transmitted to the brain, which interprets the signals as pain. Benzocaine hydrochloride is a salt modification of benzocaine, formed when benzocaine is complexed with hydrochloric acid. Compared to benzocaine, benzocaine hydrochloride is more water soluble, making it more appropriate for oral administration.
Benzocaine hydrochloride is usually made into powder or oil paste and used to heal wounds, ulcers, burns, skin abrasion, and hemorrhoids. Through the reduction in the excretion of ammonia and carbon dioxide of fish by benzocaine hydrochloride, the pH and alkalinity values of the transport water remains constant, thereby, benzocaine hydrochloride is used as an aid in the transport of fish.
 J.T. Ferreira, H.J. Schoonbee, G. L. Smit (1984) The use of benzocaine-hydrochloride as an aid in the transport of fish, Aquaculture, 42, 169-174