Paracetamol (PAM) has emerged as an important wastewater contaminant due to its wide usage. In this study, Fenton reactions were introduced to microbial fuel cells (MFCs) for bio-electrochemical degradation of PAM without external power supply. Dual-chamber MFC reactors were employed: in the anode chambers, bio-electrons were released by oxidizing biodegradable pollutants in low-strength real domestic wastewater; in the cathode chambers, the input fluxes of bio-electrons from the anode could promote the yield of free radical (OH)-O-center dot by facilitating the regeneration of iron source. Compared to conventional Fenton reactions in which no bio-electrons were transferred, our approach exhibited the advantage that no continuous addition of Fenton reagents was required in MFC-Fenton system. Significant changes in the UV-vis spectra of catholytes from an MFC-powered process strongly indicated that bio-electricity input played an important role in PAM degradation. The performance of electro-Fenton system was in good agreement with the bio-electricity output-capacity from MFC reactor under expected optimal conditions. At total iron concentration of 5 mg L-1, initial pH value of 2.0 and external resistance of 20 Omega, the highest PAM degradation efficiency of 70% was attained within 9 h. A 25% PAM could be completely mineralized while the majority was mainly converted to intermediate metabolites of p-nitrophenol via p-aminophenol and to less hazardous dicarboxylic/carboxylic acids. These results suggested that MFC-Fenton could be applied as an energy-saving and efficient approach to PAM-containing wastewater treatment, and further to non-biocompatible pharmaceuticals degradation in aquatic environment. (C) 2015 Elsevier B.V. All rights reserved.