The biotransformation of the synthetic (E,E)-1,5-cyclodecadienol 5 and (+)-hedycaryol (11) by a root suspension of fresh chicory has been investigated. Incubation of 5 with a root suspension gave a 2 : 1 mixture of the epimeric eudesmanediols 7a and 7b whereas 11 was selectively converted into cryptomeridiol (12). An explanation for the obtained results is proposed.