The aim of this study was to evaluate Pholiota aurivella extract's chemical and mineral composition, total antioxidant capacity, histopathological changes in liver and kidney, as well as its possible protective/harmful role against carbon tetrachloride (CCl4)-induced oxidative stress in rats. After the toxicity test, twenty four rats were divided into four experimental groups: Control, CCl4, CCl4+P. aurivella (100 mg/kg, extract) and CCl4+P.aurivella (500 mg/kg, extract) groups. Some biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) in serum, malondialdehyde (MDA) and antioxidant defense system (ADS) constituents such as reduced glutathione (GSH) levels, glutathione reductase (GR), glutathione S-transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities in the liver, brain and kidney tissues, histopathological changes in liver and kidney of rats were observed. P.aurivella extract was rich in phenolic (p-coumaric and protocatechuic acids) and fatty acid (linoleic, oleic and palmitic acids) compounds and high level of Arsenic. In vivo studies revealed that P.aurivella extract suppressed the levels of ADS enzymes and increased the MDA content and AST, ALT and LDH in treated groups. According to histopathological investigation, liver and kidney revealed severe histopathological changes both in CCl4 group and P.aurivella- treated groups. These results have shown that oral administration of P. aurivella extract caused a significant toxic effects in rats. Therefore, in the context of the data obtained from this study the P. aurivella could not be regarded as a safe food source.