Background: Rutin has several health benefits like improving total antioxidant capacity(TAC), inducing more nitric oxide(NO) produced from endothelium, and anti-inflammatory. Studies show rutin can enhance sport performance in mouse, but there isn't any human trail suggests that rutin can improve sport performance in high-stressed state. Purpose: This study want to investigated the effects of rutin on oxidative stress, inflammatory markers, and blood flow velocity in 40km time trial. Method: A single-blinded crossover placebo-controlled study design is used and rutin supplementation is compared to a non-treatment control group. Twelve subjects are randomly assigned into two groups supplemented with the dose of 2000mg/day rutin or placebo for two weeks. All subjects participate 40km cycling time trails(TT) after rutin or placebo supplement. Venous blood samples are drawn before meal, before exercise and immediately after the exercise in order to estimate malondialdehyde(MDA) levels, TAC, Interleukin 10(IL-10), tumor necrosis factor-alpha(TNF-a), and high-sensitivity C-reactive protein(HS-CRP). In TT, blood flow velocity is monitored by near infrared spectroscopy(NIRS) and HR rating of perceived exertion(RPE) and rating-of-fatigue (ROF) scale are also recorded. Expected results:14 days rutin supplementation can improve 40km TT performance by reducing exercise-induced oxidative stress and enhancing blood flow velocity in healthy young adults.