Guaiacwood oil is a fragrance ingredient used in soap and perfumery. It comes from the palosanto tree (Bulnesia sarmientoi). Bulnesia sarmientoi was listed as endangered in the 2018 publication of the IUCN Red List, due to the deforestation of Gran Chaco and a strong global demand for its wood, extracts, and essential oils since 2001. IUCN estimates indicate that over three generations the global population will decline by around 50%.
Guaiac wood oil is produced through steam distillation of a mixture of wood and sawdust from palosanto. 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
Guaiac wood oil 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.