Rice stem was treated with subcritical water at 260°C for 0-20 min. The extracts treated for 5 min were subject to re-treatment for 0-60 min. In the further treatment, the total phenolic content, total carbohydrate content, radical scavenging ability, and metal chelating ability decreased with extended treatment time. Tyrosinase inhibition ability, however, did not depend on the treatment time. There were correlations between the total phenolic content and radical scavenging ability and between the total carbohydrate content and metal chelating ability under any treatment conditions.