Of all the members of the animal kingdom the human being is the one that comes most intimately and oftenest in contact with deleterious substances, either as medicines or in the arts and crafts. The deleterious effects of medicines have been recognized for many years. Carolus Rueus, Soc. Jesu, long ago drew attention to the Greek word pharmacon (hence our word, pharmacy), which sometimes meant a remedy and sometimes a poison.1
The learned, Jesuit commentator on Virgil, Carolus Rueus, stated: "Pharmacon enim ambigua vox est: et modo remedium modo venenum significat." (The word pharmacon is indeed ambiguous and sometimes means a remedy and sometimes a poison). Rueus, Carolus, in P. Virgilii Maronis Opera, edition by John Cary, London, 1835.
The physician observing the deleterious effects of medicines in his practice runs the danger of becoming overcautious, a disastrous frame of mind. This timidity is often still further exaggerated by
MONTGOMERY DW. THERAPEUTIC TIMIDITY. Arch Derm Syphilol. 1936;33(6):1018–1021. doi:10.1001/archderm.1936.01470120069009