Applied Plant Sciences Program, Kangwon National University, Chuncheon 200-701, KoreaAbstract - There has been little research on the harvesting time-dependent changes in the antioxidant activities of new varieties of highland cultures of Gomchwi (Ligularia fischeri) crossed with Turcs (Ligularia fischeri (Ledeb.)) and Nakai (Ligularia fischeri var. spiciformis), namely Sammany (S), Gommany (G) and Damogy (D). This study was conducted to assess the effect of different harvesting times on nutritional and health-related properties such as total phenolic contents, flavonoids, DPPH (1,1-diphenyl-2-picrylhydrasyl) free radical scavenging activities and reducing power. From these harvests, extracts were prepared using methanol. Total phenolic content in Jul 14-G (Gommany harvested on July 14, 0.172 ㎎·GAE/㎖) was higher than that in other products harvested after the same period (S, 0.154; D, 0.141 ㎎·GAE/㎖). Flavonoid content was higher in Jul 3-G (0.114 ㎎·QE/㎖), compared to Jul 3-S (0.113 ㎎·QE/㎖) and Jul 14-D (0.089 ㎎·QE/㎖). Antioxidant activities were higher in samples harvested after June 12 in all cases. On July 14, the highest DPPH free radical scavenging activities among all harvest dates were seen (92.875~94.595%). The reducing power was also dependent on harvest day (Abs 0.5~0.6 on July 14), showing a pattern similar to that of DPPH free radical-scavenging activities. Antioxidant activity and harvesting times seem to correlate with total polyphenol and flavonoid contents.