The objective of this study was to investigate the effect of the presence of an activated carbon cloth (ACC) during the degradation and removal of gallic acid (GA) and p-coumaric acid (pCA) by Fenton oxidation using H2O2 and FeSO4 as catalyst. Removal of GA or pCA by Fenton oxidation was much higher than that of total organic carbon (TOC), indicating that a large proportion of GA or pCA degradation products was not mineralized. The presence of ACC increased the concentration of hydroxyl radicals generated in the FeSO4 + H2O2 system. The presence of ACC during Fenton oxidation largely increased TOC and GA removal, attributable to the adsorption of GA and its degradation products and the increased generation of OH(•) radicals that mineralize them. In the Fenton oxidation of pCA, the presence of ACC produced the same effects as for GA, but now the increased removal of pCA was due to adsorption on the activated carbon and not to the increased generation of hydroxyl radicals, due to the greater affinity of pCA for the carbon surface and its more difficult mineralization in comparison to GA.