We report two cases of hyperemesis gravidarum with hyperthyroidism and jaundice. The cessation of vomiting associated with supportive care was followed by complete recovery in 5 weeks. Hyperthyroidism occurs in 60% of hyperemesis gravidarum, but jaundice is uncommon. The association of jaundice and hyperthyroidism suggests that hyperthyroidism is a possible factor of cholestasis in patients with hyperemesis gravidarum.