Conium maculatum is known as highly toxic plant, due to piperidine alkaloids present in the aerial parts. In a first attempt, in various tap root samples, however, alkaloids could not be detected. The present study describes active compounds in the tap roots from 16 populations harvested at maturity. The compounds were extracted with dichloromethane from root pieces of single plants and analyzed by gas chromatography-mass spectrometry. Ten bioactive compounds were evaluated: five furocoumarins, two prenylated coumarins, two aliphatic C17-polyacetylenes and the phenylpropanoid elemicin. A high variability could be observed, the highest concentrations were measured for falcarindiol, xanthotoxin and isopimpinellin, the lowest for elemicin. In sum C. maculatum roots contained comparable amounts of compounds that are characteristic for Apiaceae, and also occur in vegetables as carrots, parsnip, parsley or celeriac.