Antioxidative properties of hydrophilic extracts prepared from the fruiting body and spent culture medium of Flammulina velutipes were evaluated by monitoring the total reducing power ability (RPA) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity (RSA), together with antioxidative activities against lipid oxidation in homogenates of yellowtail dark muscle and autoxidation of oxymyoglobin (oxyMb) purified from yellowtail dark muscle. Generally, all of the extracts had RPA, RSA and antioxidative activities against lipid oxidation and oxyMb autoxidation. Extracts prepared from the fruiting body of F. velutipes with a higher ergothioneine (ESH) content exhibited a stronger delay of the autoxidation activity of oxyMb, whereas extracts prepared from the spent culture medium of F. velutipes with higher phenolics content showed more efficient antioxidant capacity against lipid oxidation. On the other hand, the amount of ESH was distributed highest in the inedible (base and mycelium) parts of the mushroom. These results suggest that the inedible parts and spent culture medium of F. velutipes could potentially be considered as a potent and readily available source of natural antioxidants. (C) 2010 Elsevier Ltd. All rights reserved.