The electrochemical reduction of coumarins on glassy carbon and electrodeposited metal electrodes was investigated in a Britton-Robinson buffer (pH 1.87-11.98). The effects of various factors, such as the deposition material, time, and concentration of mercury, on the precision of the analysis were explored. The possible reaction mechanism of the reduction process with regards to scan rates, peak potentials, and currents is discussed. Electroreduction was used to quantitatively determine the levels of coumarins in some essential oils and traditional Chinese herbal medicines. A comparison with high performance liquid chromatography analysis results shows good agreement.