Abstract Background Hyperemesis gravidarum (HG) is a common complication during pregnancy, however, HG associated simultaneous onset of blood cell destruction due to electrolyte abnormalities is rare. In this case, a woman with refeeding syndrome (RFS) secondary to electrolyte abnormalities caused by severe HG was diagnosed and managed in our hospital. Case presentation A 29-year old woman was sent to the local hospitals because of severe HG with appetite loss, weight reduction, general fatigue, and she was identified to have severe electrolyte abnormalities. However, the electrolyte abnormalities were not corrected promptly, and then she had the symptoms of stillbirth, altered mental status, visual hallucination, hemolytic anemia and thrombocytopenia. After transferred to our hospital, we continued to correct the electrolyte abnormalities and the labor induction was performed as soon as possible. The symptoms of blood cell destruction were relieved obviously, and the patient discharged four days later. The electrolyte disturbances and physio-metabolic abnormalities caused by HG helped us diagnose this case as RFS. Conclusions This case emphasizes that patients with RFS should be diagnosed appropriately and intervened promptly in order to prevent electrolyte imbalance induced blood cell destruction.