The interaction of lycorine (LYC) with calf thymus double stranded DNA (dsDNA) and calf thymus single stranded DNA (ssDNA) was studied electrochemically based on the oxidation signals of guanine and adenine by using differential pulse voltammetry (DPV) at carbon paste electrode (CPE) and pencil graphite electrode (PGE). As a result of the interaction of LYC with DNA, the voltammetric signal of guanine and adenine greatly decreased. The changes in the experimental parameters such as the concentration of LYC, and the accumulation time of LYC were studied by using DPV with PGE. The interaction of LYC with synthetic polynucleotides, such as poly[G] was also observed. The interaction of LYC with dsDNA was also observed at PGE in solution phase. In addition, the detection limit and the reproducibility was determined by using both electrochemical transducers. The application of electrochemical methods on the interactions between DNA and DNA targeted agent were explored. (C) 2003 Elsevier B.V. All rights reserved.