To examine the potential role of ROS in CH induced effects on hERG currents and protein in SH-SY5Y cells, we first determined cellular ROS levels in CH exposed cells by two approaches: one by staining of cells with H2DCFDA, a cell permeable indicator of ROS that is fluorescent upon oxidation and the other by determining the aconitase enzyme activity, an established biochemical marker of ROS in cytosol and mitochondrial fractions. This evidence concerns the gene KCNH2 and cyclic hematopoiesis.