Geraniol

Geraniol is a volatile fragrance ingredient extracted from geranium. Geraniol is capable of causing sensitivity when applied to skin. However, the risk of such reaction has to do with depth of penetration into skin, and geraniol doesn’t penetrate skin easily. As such, although it’s not a great ingredient to see on a label if you have sensitive skin, it isn’t among the most troublesome fragrance ingredients when used in low concentrations. Despite the lesser concern, research has shown that, like many fragrant oil components, geraniol can oxidize in the presence of air, causing damage when applied to skin’s surface.

See: Geranium Pratense