Cinnamic acid and its related compounds are commonly found in plants and animals in the form of amino acids and glycolic acid. Cinnamic acid is phenylalanine and its derivatives of enzymatic deamidation of amino substituents, through the side chain of the reductive oxidation, reduction into phenylpropionic acid, in monkeys, rats, brood intestines and rabbits can be found in trace amounts of phenylpropionic acid in the urine. Human oral cinnamic acid metabolites for single cinnamyl glucuronide and horse uric acid, should lah relevant compounds including cinnamic acid, cinnamaldehyde, cinnamyl alcohol, cinnamon cool for pharmaceutical food additives, a variety of cinnamic acid vinegar and cinnamyl alcohol analogues used as medicines, cleansing and food flavoring and seasoning. Clean and food spices and flavoring agents, after long-term consumption have not found side effects. However, due to the chemical structure of cinnamic acid and toxic compounds styrene and incense 1, see the structure of the similarity of the elements, all have styrene groups, therefore, the European flash and "{ month FDA and the United Nations Health, FAO and so on these kinds of chemical medium that is the human body's maximum daily intake (ADI) and food, drugs, and shares of the remaining amount of regulations. For example, the provisions of cinnamic acid, cinnamic acid vinegar and cinnamaldehyde ADI of 1.25 mg/kg, a substitution of various cinnamaldehyde for 1 ppm, a a pentyl cinnamyl alcohol plus PPm, o-aminobenzoic acid cinnamyl alcohol (Cin a larnylanthranilate) for 25 ppm, etc., and whether it has been owed to zr from the folding of the cinnamic acid compounds, we must ensure its safety. The toxicity of cinnamic acid is very low, the total sex ID tears of rats, mice and pie rats are more than 5000 mg/kg.