Oryeong-san which was first recorded in Shanghanrun describing the treatments of acute febrile disease is one of the frequently used oriental medicines. Oryeong-san has been prescribed for the treatment of symptoms accompanied by edema. The purpose of this study was to examine the diuretic effects of Oryeong-san by different routes of administration. Oryeong-san (100 mg/kg body weight) was administrated by three different routes in Sprague-Dawley rats: intravenous infusion, intraperitoneal injection and oral intake. Oral intake of Oryeong-san significantly increased urinary volume and excretion of $Na^+$, $Cl^-$, and $K^+$ compared to vehicle-treated control group. The effects were concentration-dependent. Intravenously administrated Oryeong-san increased urinary volume and electrolyte excretion but without significance in hydrated (0.02 ml/min/rat for 90 min) anesthetized rats. Similarly, intraperitoneally injected Oryeong-san had no effects on water and urine electrolyte excretion compared with saline control group. These findings suggest that Oryeong-san has different effects on water and electrolyte balance by routes of administration.