Proton leak has been implicated in various chronic diseases like diabetes and cancer. In this study, current from intact cells, including mice liver cells, pig blood cells and human breast cancer cell MCF-7 were measured by microbial fuel cells (MFC). Positive current change in normal liver cells were induced by either 2,4-dinitrophenol (DNP) or Piceatonnol. The effect of DNP in enhancing the proton conductivity would increase the degree of positive current change, while Piceatonnol in improving the mitochondria membrane potential would support the sustainability of the positive current change with time. Piceatonnol was found to be more effective in inducing positive current change in cancer cells than in liver cells. The higher effectiveness of Piceatonnol to cancer cells would be explained by the high proton leak condition of the cells, and so increased the current production. Little positive current change could be induced in red blood cell by either DNP or Piceatonnol. Results supported the hypothesis of the high mitochondria membrane potential to support the positive current change in cells with time, while the proton conductivity determined the degree of positive current change. The condition of proton leak of cells seemed to be the limiting factor for the positive current change in cells.