Normal levels of total furocoumarins in fresh parsnip roots are as high as 96 ppm (wet weight). In older spoiled and diseased parsnips freely available in grocery stores these values may be increased by 2500%. So high are the amounts in some instances, that mixed crystals of furocoumarins can be detected on the surfaces of the parsnip roots by both conventional low powered microscopy and SEM. The principal crystal form was angelicin but the presence of psoralen, 5-MOP and 8-MOP was confirmed by HPLC, TLC, photobiological assay and analysis of mass spectra.