Aim and objective: To compare 5% dextrose–Ringer's lactate against Ringer's lactate solution in the intravenous rehydration of grade II hyperemesis gravidarum. Materials and methods: The research was conducted in Wahidin Sudirohusodo Hospital and the network education hospitals, using the prospective cohort method. The total samples were 66 subjects meeting the criteria and randomly assigned to receive either the 5% dextrose–Ringer's lactate or Ringer's lactate group by intravenous infusion at a rate of 125 mL/hour over 24 hours in a randomized clinical trial. All participants received neurotropic and antiemetics intravenously as well. Oral intake was not allowed. Primary outcomes were resolution of blood electrolytes and ketonuria after 24 hours. Results: There was a significant increase of the levels of blood electrolyte (hyponatremia, hypokalemia, and hypochloremia) and resolution of ketonuria after the first 24 hours of both groups. Yet, the mean increase of the levels of the blood electrolyte and resolution of ketonuria was insignificant for both groups; however, the increase of the blood electrolyte potassium level was greater in the group treated with 5% dextrose–Ringer's lactate. At the value of 95% CI, the mean increase of the blood potassium levels in the 5% dextrose–Ringer's lactate group and Ringer's lactate was 0.31 and 0.20 mmol/L, respectively (p 0.044). Conclusion: Intravenous rehydration with 5% dextrose–Ringer's lactate or Ringer's lactate solution in women hospitalized for grade II hyperemesis gravidarum produced similar outcomes, other than that for the greater value of potassium electrolyte in 5% dextrose–Ringer's lactate group.