Background: Hyperemesis gravidarum is characterized by intractable vomiting and associated with weight loss exceeding 5% of prepregnancy body weight, dehydration, and ketosis. Hyperemesis gravidarum occurs during the first trimester and typically resolves by 16 to 20 weeks of gestation. Approximately half of all hospitalized females with hyperemesis gravidarum have a mild elevation in liver enzymes; however, jaundice and hepatic synthetic dysfunction are uncommon. Case Report: A 22-year-old gravida 1 para 0 in her ninth week with a singleton gestation was hospitalized with persistent nausea, vomiting, weight loss of 11% of her prepregnancy body weight, dehydration, hypokalemia, and jaundice. Liver function tests showed hyperbilirubinemia of 7.1 mg/dL and alanine aminotransferase levels high as 676 U/L. Other hepatobiliary diseases were excluded. Thyroid function tests revealed thyrotoxicosis. Gestational thyrotoxicosis is often associated with hyperemesis gravidarum because of their shared pathophysiology of high human chorionic gonadotropin levels during the first trimester. After supportive management including hydration, correction of electrolyte disturbance, vitamin supplementation, and antiemetic treatment, the patient's symptoms resolved. Liver and thyroid dysfunction returned to normal after resolution of vomiting. The patient delivered a healthy child at 38 weeks' gestation. Conclusion: Elevation of aminotransferase and bilirubin levels may occur in patients with hyperemesis gravidarum. Although jaundice and highly elevated liver enzymes have been reported, investigations to exclude preexisting and concurrent liver diseases are required. Management of hyperemesis gravidarum is supportive, and outcomes are generally favorable.