Guaiacwood oil is a fragrance ingredient used in soap and perfumery. It comes from the palosanto tree (Bulnesia sarmientoi).
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.