Micro Fourier transform infrared spectroscopy enables one to study small samples because of the high quality spectra that can be obtained. Biochemical and morphological changes between control and pathological tissues of head and neck tumours have been monitored drawing three-dimensional chemical maps of the main vibrational modes in the regions of interest. Comparison between spectral and histological data shows a satisfactory degree of accordance. Among all, proliferating and regressive states of the tumours can be identified.