The interaction of native calf thymus DNA with butylated hydroxyanisole (BHA) at physiological pH was investigated by spectrofluorometric, voltammetric, and viscosimetric techniques. BHA molecules intercalated between base pairs of DNA, demonstrated by a sharp increase in specific viscosity of DNA and decreases in the fluorescence of BHA solutions in the presence of increasing amounts of DNA and calculated formation constant (K(f)) at different temperatures. Further, the enthalpy and entropy of the reaction between BHA and calf thymus DNA showed that the reaction is exothermic and enthalpy favored (DeltaH = -89.02 kJ/mol; DeltaS = -211.21 J/mol K). Also, peak current decrease and positive shift in the cyclic voltammetry indicate that BHA is able to intercalate in the DNA base pairs.