A new bakkenolide-type compound, bakkenolide-Va(1), was isolated from the rhizome of Petasites tricholobus. The structure was characterized on the basis of various NMR (1H, 13C, 1H–1H COSY, HMQC, HMBC and NOESY) and mass spectrometry data. The neuroprotective activity of bakkenolide-Va was investigated in primarily cultured neurons treated by hypoxia-glucose deprivation and various types of oxidative insults.