Cinnamomum cassia oil is an essential oil extracted from the leaves and twigs of the Chinese cinnamon tree, the cinnamon cassia. The oil is mainly used in oral care products. It cleanses, deodorizes and protects the oral cavity; reduces or inhibits the basic smell or taste of a product; makes the hair easier to comb, supple, softer and shinier and gives it more volume. Cinnamomum cassia oil is occasionally used as a fragrance. The oil is toxic and should not be used directly on the skin (risk of sensitization, see below). Cinnamaldehyde an ingredient of Cinnamomum cassia oil).