The UV-visible results of this kinetic study show that amphothericin B as Fungizone is a much stronger oxidant than CuSO4, itself a powerful oxidant of low-density lipoprotein (LDL), Amphotericin B as AmBisome alone has no oxidizing effect on LDL while a mixture of both AmBisome and CuSO4 induces an important potentialization of the LDL oxidation. These results allow us to believe that the high toxicity of amphotericin B is related to its capacity to modify and to weaken the structure of LDL. In addition, differential scanning calorimetry experiments show that the oxidative modifications of LDL by CuSO4 or by amphotericin B proceed through different mechanisms. (C) 2000 Federation of European Biochemical Societies.