To increase the analytical potential of the combination of gas chromatography and Fourier-transform infrared spectrometry, we have adapted our system to use of capillary columns, and automated the acquisition and treatment of the data. The performance of the method was tested by analysis of complex mixtures such as the essential oils of peppermint and lavender. The sensitivity and resolution are poorer than those obtained with classical GC detectors but the spectra are very useful for determining molecular structure.