During antiquity, pitches and resins were used commonly as medicines. Pliny mentions a variety of tar-like substances being used as medicine, including cedria and pissinum.Cedria was the pitch and resin of the cedar tree, being equivalent to the oil of tar and pyroligneous acid which are used in the first stage of distilling creosote. He recommends cedria to ease the pain in a toothache, as an injection in the ear in case of hardness of hearing, to kill parasitic worms, as a preventative for impregnation, as a treatment for phthiriasis and porrigo, as an antidote for the poison of the sea hare, as a liniment for elephantiasis, and as an ointment to treat ulcers both on the skin and in the lungs. He further speaks of cedria being used as the embalming agent for preparing mummies. 
Pissinum was a tar water that was made by boiling cedria, spreading wool fleeces over the vessels to catch the steam, and then wringing them out. The Pharmacope of Lyons, published in 1786, says that cedar tree oil can induce vomiting, and suggests it helps medicate tumors and ulcers. Physicians contemporary to the discovery of creosote recommended ointments and pills made from tar or pitch to treat skin diseases.
Tar water had been used as a folk remedy since the Middle Ages to treat affections like dyspepsia. Bishop Berkeley wrote several works on the medical virtues of tar water, including a philosophical work in 1744 titled Siris: a chain of philosophical reflexions and inquiries concerning the virtues of tar water, and divers other subjects connected together and arising one from another, and a poem where he praised its virtues.
Pyroligneous acid was also used at the time in a medicinal water called Aqua Binelli. Given this history, and the anti-septic properties known to creosote, it became popular among physicians in the 19th century. A dilution of creosote in water was sold in pharmacies as Aqua creosoti, as suggested by the previous use of pyroligneous acid. It was prescribed to quell the irritability of the stomach and bowels and detoxify, treat ulcers and abscesses, neutralize bad odors, and stimulate the mucous tissues of the mouth and throat.
Creosote in general was listed as an irritant, styptic, anti-septic, narcotic, and diuretic, and in small doses when taken internally as a sedative and anaesthetic. It was used to treat ulcers, and as a way to sterilize the tooth and deaden the pain in case of a tooth-ache. Creosote was suggested as a treatment for tuberculosis by Reichenbach as soon as 1833. Following Reichenbach, it was argued for by John Elliotson and Sir John Rose Cormack. Elliotson, inspired by the use of creosote to arrest vomiting during an outbreak of cholera, suggested its use for tuberculosis through inhalation. He also suggested it for epilepsy, neuralgia, diabetes and chronic glanders. The idea of using it for tuberculosis failed to take hold, and use of this purpose was dropped, until the idea was revived later in 1876 by the British doctor G. Anderson Imlay, who suggested it be applied locally in spray to the bronchial mucous membrane. This was followed up in 1877 when it was argued for in a clinical paper by Charles Bouchard and Henri Gimbert.
Germ theory had been established by Pasteur in 1860, and Bouchard, arguing that a bacillus was responsible for the disease, sought to rehabilitate creosote for its use as an antiseptic to treat it. He began a series of trials with Gimbert to convince the scientific community, and claimed a promising cure rate. A number of publications in Germany confirmed his results in the following years. Following that, that was a period of experimentation of different techniques and chemicals using creosote in tuberculosis, which lasted until about 1910, when radiation therapy looked to be a more promising treatment.
Guaiacol, instead of a full creosote solution, was suggested by Hermann Sahli in 1887; he argued it had the active chemical of creosote and had the advantage of being of definite composition, and with less of a less unpleasant taste and odor. A number of solutions of both creosote and guaiacol appeared on the market, such as phosphotal and guaicophosphal, phosphites of creosote and guaiacol; eosot and geosot, valerinates of creosote and guaicol; phosot and taphosot, phosphate and tannophospate of creosote; and creosotal and tanosal, tannates of creosote. Creosote and eucalptus oil were also a remedy used together, administered through a vaporizor and inhaler. Since then, more effective and safer treatments for tuberculosis have been developed. In the 1940s, Canadian-based Eldon Boyd experimented with guaiacol and a recent synthetic modification - glycerol guaiacolate (guaifenesin) - on animals. His data showed that both drugs were effective in increasing secretions into the airways in laboratory animals, when high enough doses were given.