['Uric acid is a well known antioxidant; however, the relationship between serum uric acid levels and oxidative stress-caused disorders including cardiovascular diseases is not clear yet. Transthoracic Doppler echocardiographic measurement of coronary flow reserve is a useful tool to investigate coronary flow reserve and coronary microvascular functions. In this study, we investigated the possible association between serum uric acid concentrations and coronary flow reserve in healthy adults.', 'One hundred healthy volunteers with normal uric acid levels, between 18 and 55 years of age, were included in this study. The study group was divided into two with regard to the serum uric acid levels. Coronary diastolic peak flow velocities were measured at baseline and after dipyridamole infusion (0.56 mg/kg over 4 min) using echocardiography.', 'Coronary flow reserve and hyperemic mean peak flow velocity were significantly greater in participants with lower serum uric acid concentrations (< or =234 micromol/l for women, < or =302 micromol/l for men) than in those with higher serum uric acid concentrations (>234 micromol/l for women, >302 micromol/l for men) (2.91+/-0.5 vs. 2.47+/-0.5, P<0.001; 66.8+/-11.4 vs. 61.1+/-16.5, P=0.04). The baseline mean peak flow velocity was significantly greater in participants with higher serum uric acid concentrations than in those with lower serum uric acid concentrations (24.7+/-4.1 vs. 23.1+/-2.4, P=0.02).'] Are coronary flow reserve and coronary microvascular functions strongly related to serum uric acid concentrations in healthy adults?