Cinnamon is strongly antibacterial and antifungal, and is a good support for the immune system, but should be used with caution since it is a strong skin irritant. It is antiseptic and warming, and can be used as a digestive stimulant and respiratory support. It is stimulating and tonifying for the nervous system. However it is important to distinguish between the oil derived from the bark, and that from the leaf, since they have different makeups and different qualities. The oil from the bark has that familiar warm, spicy and sweet aroma. It is a strong skin irritant so this method of use is not recommended, although it can safely be used in a diffuser. The oil from the leaf has similar therapeutic properties, but it can be used with caution on the skin but in very low dilutions (0.5%). Aromatically it is more akin to Clove, than cinnamon.  Cinnamon oil blends well with Clove, Orange, Mandarin, Frankincense, and Cedar.