the use of chemometric methods in the analysis of Raman and IR spectra of dyes has opened new possibilities in the areas previously reserved only for chromatographic methods or conventional uv-vis studies. this chapter is focused on the analysis of natural dyes, especially carotenoids, flavonoids, anthraquinones and indigoids presented in biological samples e.g. plants or food. the discussed chemometric methods are implemented both in the qualitative and quantitative determination of colorants with the techniques of vibrational spectroscopy