A simple protocol for DNA isolation from dry roots ofBerberis lycium is described. Four-year-old dry roots are used, and the isolated DNA is suitable for analysis by means of restriction enzyme digestion and random amplification of polymorphic DNA (RAPD). The method involves a modified CTAB procedure using 1% PVP to remove polysaccharides and purification using low-melting-temperature agarose. DNA is amplified by means of PCR using 10-mer random primers from Operon Biotechnologies, Inc. (USA), and DNA samples are digested withTaq I,Hind III andEcoR I and examined on agarose gels. The RAPD reaction is performed according to the 1990 protocol by Williams et al.