Scientific evaluations of the effects of fragrances on humans are rather scarce. The aim of this investigation was to study the effects of ylang-ylang oil (Cananga odorata, Annonaceae) on hu-man physiological parameters and self-evaluation. Twenty-four healthy volunteers participated in the experiments. Fragrances were administered by inhalation. Physiological parameters recorded were skin temperature, pulse rate, breathing rate and blood pressure. Self-evaluation was assessed in terms of alertness, attentiveness, calmness, mood, relaxation and vigor. Additionally, fragrances were rated in terms of pleasantness, intensity and effect. The present investigation showed that ylang-ylang oil may be characterized by the concept of "harmonization" rather than relaxation/sedation. Compared to an odorless placebo, ylang-ylang oil caused significant decreases in blood pressure and pulse rate as well as significant increases of subjective attentiveness and alertness. Correlational analyses revealed that the observed effects are mainly due to a subjective odor experience.