TCP is a mild antiseptic, produced and sold in the United Kingdom by Pfizer. The brand name comes from its original chemical name, which was Trichlorophenylmethyliodosalicyl (not to be confused with Trichlorophenol, a common fungicide).

Trichlorophenylmethyliodosalicyl was replaced as the active ingredient by a mixture of phenol and halogenated phenols in the 1950s. The liquid form of TCP is one of the most well-known brands of antiseptic in the UK, and its distinctive sweet, medicinal odour can be identified by many as the generic smell of antiseptic.

TCP is available in 50 ml, 100 ml, 200 ml and 500 ml bottles as a clear yellow liquid. It is also available as a cream and as throat lozenges.

TCP can be used on the following conditions:

Sore throats - Gargle a solution of TCP with 5 parts water twice a day. Do not swallow.

Mouth ulcers - Dab undiluted three times a day.

Cuts, grazes, bites and stings - Dilute 1 part TCP with 1 part water and apply freely. (TCP may be used undiluted in an emergency).

Boils, spots and pimples - Dab undiluted once every four hours.

TCP can also be used as a mouthwash when diluted, and can also be used as a general disinfectant.