In this work, bioactive compounds present in flower heads of German Chamomille, were extracted and isolated in pure forms by chromatographic techniques. These compounds, spiroketal enol ethers, present in both isomeric forms Z and E, were characterized and unequivocally identified by spectroscopic techniques. One- (H-1, C-13) and two-dimensional (H-1-H-1-COSY, H-1-H-1-NOESY, HMQC and HMBC) NMR were used to assign the configuration of each isomeric compound. It was also found that irradiation of the extracts with UV light induced the photoisomerization of the en-yn-dicycloethers favoring the formation of the more stable E isomer.