Ylang-ylang oil had a sedative-like effect in one randomized controlled trial (RCT), reducing reaction time and the how quickly participants were able to recall words;[1] however, in contrast, it increased attentiveness and alertness in 1 of 2 other RCTs.[2][3]
Ylang-ylang oil has been approved for use as a flavoring agent in food by the US Food and Drug Administration and is Generally Recognized As Safe (GRAS) by the Flavor and Extract Manufacturers Association.[4][5] The quantities used in food are minuscule and may amount to an average consumption of 0.00062 mg per day for the average individual in the US.[4]
In aromatherapy, where there can be contact with much larger amounts of the essential oil, there have been case reports of people having mild to moderate contact dermatitis (an allergic reaction) on their skin.[6] It may be an aromatherapy plant with a relatively higher risk of side effects, as a 2012 systematic review of adverse effects of aromatherapy examined 42 case reports and found that ylang-ylang was the 3rd most common plant to have adverse effects (6 case reports).[6] A 2017 narrative review found that the majority (11 of 13) of the case reports of contact dermatitis from essential oils occurred in occupational exposures by aromatherapists or massage therapists, who can be exposed to large amounts of essential oils over time.[7]