Oil of guaiac

Oil of guaiac is a fragrance ingredient used in soap and perfumery. Despite its name it does not come from the Guaiacum tree, but from the palo santo tree (Bulnesia sarmientoi).{{cite web|url=http://www.fragrantica.com/notes/Guaiac-Wood-36.html |title=Guaiac Wood perfume ingredient, Guaiac Wood fragrance and essential oils Bulnesia sarmienti |publisher=Fragrantica.com |date=1921-04-04 |access-date=2016-01-14}}

Oil of guaiac is produced through steam distillation of a mixture of wood and sawdust from palo santo. It is sometimes incorrectly called guaiac wood concrete. It is a yellow to greenish yellow semi-solid mass which melts around 40–50 °C. Once melted, it can be cooled back to room temperature yet remain liquid for a long time. Oil of guaiac has a soft roselike odour, similar to the odour of hybrid tea roses or violets. Because of this similarity, it has sometimes been used as an adulterant for rose oil.{{cite book|last1=Guenther|first1=Ernest|title=The Essential Oils: Individual Essential Oils of the Plant Families|date=1992|publisher=Krieger Publishing Company|isbn=9780894647734|pages=28, 197–9|url=https://books.google.com/books?id=mjTmAAAAIAAJ&q=%22Oil+of+guaiac%22|access-date=19 October 2017|language=en}}

Oil of guaiac is primarily composed of 42–72% guaiol, bulnesol, δ-bulnesene, β-bulnesene, α-guaiene, guaioxide and β-patchoulene. It is considered non-irritating, non-sensitizing, and non-phototoxic to human skin.

Oil of guaiac was also a pre-Renaissance remedy to syphilis.