The level of plasma leakage is mild to moderate in patients with non-shock dengue hemorrhagic fever (DHF grade I and grade II), and the necessity of intravenous fluid replacement for these patients remains controversial. We conducted an observational study in adult patients (>18 years) with non-shock DHF admitted to a medical centre in southern Taiwan comparing the effects of oral hydration [group 1 (n=19); age (mean+/-SD) 54.6+/-15.5 years] and intravenous fluid replacement, with a volume of >40ml/kg/day in the first 72h of hospitalization [group 2 (n=30); age 55.9+/-11.6 years]. No significant difference was found in demographics, clinical manifestations, and mean peak level of hematocrit between the two groups. Patients in group 2 had a significantly longer hospital stay compared to those in group 1 (P=0.007), and there was a trend suggesting patients in group 2 were prone to develop pleural effusion and/or pulmonary edema. No difference was found in daily mean pulse pressure, mean hematocrit level, and mean platelet count between the groups for the duration of the 7 days in hospital. All 49 patients survived. Our data suggest that oral hydration may be as effective as intravenous fluid replacement for adults with non-shock DHF and this warrants investigation in a larger series of patients.