Cinnamic acid is an organic compound with the formula C6H5-CH=CH-COOH. It is a white crystalline compound that is slightly soluble in water, and freely soluble in many organic solvents. Classified as an unsaturated carboxylic acid, it occurs naturally in a number of plants. It exists as both a cis and a trans isomer, although the latter is more common.

Storax, often commercially sold as styrax, is a natural resin isolated from the wounded bark of Liquidambar orientalis Mill. and Liquidambar styraciflua L. (Hamamelidaceae). It is distinct from benzoin, a similar resin obtained from the Styracaceae plant family.