Cassia

The tree grows to 10–15 m (33–49 ft) tall, with greyish bark and hard, elongated leaves that are 10–15 cm (3.9–5.9 in) long and reddish when young.

The part of the bark that is used to make spices is called the Cinnamomi cortex. Chinese cassia (called ròuguì; 肉桂 in Chinese) is produced primarily in the southern provinces of Guangxi, Guangdong, and Yunnan. It is considered one of the 50 fundamental herbs in traditional Chinese medicine. More than 160 phytochemicals have been isolated from Cinnamomum cassia. Coumarin found in C. cassia could damage the liver if consumed in larger amounts, therefore European health agencies have warned against consuming high amounts of cassia. (Coumarin is not influencing blood coagulation, but Dicoumarol, formed from Coumarin, does.) Other bioactive compounds found in the bark, powder and essential oils of C. cassia are cinnamaldehyde and styrene. In high doses, these substances can also be toxic to humans.

A mention by Chinese herbalists suggests that cassia bark was used by humans at least as far back as 2700 B.C. It was a treatment for diarrhea, fevers, and menstrual issues. Cassia cinnamon was brought to Egypt around 500 B.C. where it became a valued additive to their embalming mixtures. The Bible suggests that it was part of the anointing oil used by Moses. The Greeks, Romans and ancient Hebrews were the first to use cassia bark as a cooking spice. They also made perfumes with it and used it for medicinal purposes. Cinnamon migrated with the Romans. It was established for culinary use by the 17th century in Europe.