Suspected drug products can be analysed by Raman spectroscopy to confirm the nature of the material. Small differences can be identified from the Raman analysis (ex: cocaine HCl / free base cocaine). By confocal Raman spectroscopy, traces can be identified on surfaces or in vials transparent to the visible excitation wavelength (glass, polymer..). Mixtures of different drug compounds or mixtures of a drug substance with additives (cutting agents) can give characteristic Raman features allowing the determination of the nature of each component and the generation of Raman maps showing their distribution.