The random amplified polymorphic DNA (RAPD) assay is a useful method for detecting genotoxin-induced DNA damage. In the present study, this assay was evaluated to measure the essential oil of Prangos ferulacea-induced DNA changes in Ephestia kuehniella Zeller larvae. The third instar larvae of E. kuehniella were exposed to 500 mu l L-1 essential oil for 24 h. Forty random primers were used for RAPD-PCR of which eleven produced unique polymorphic band patterns. In comparison with control larvae, the essential oil-treated larvae showed greater changes in RAPD profiles. This is the first report of an analysis of the genotoxic effect of P. ferulacea essential oil against E. kuehniella larvae using RAPD-PCR.