Immunohistochemistry of hyperemesis gravidarum is an adjunctive test when pathology is difficult to identify. Since the morphology of complete and partial hyperemesis gravidarum is similar, therefore, in addition to routine pathology reading, immunohistochemistry auxiliary testing is also needed to accurately diagnose. Immunohistochemistry for hyperemesis gravidarum includes P57, Ki67, P53, etc., which can be analyzed according to the results of the test: P57 can distinguish partial hyperemesis gravidarum from complete hyperemesis gravidarum; the higher the proliferation index of Ki67, the faster the proliferation; and the higher the value of P53, the higher the likelihood of malignant transformation. When suspected of hyperemesis gravidarum, one should go to a regular hospital for consultation and treatment under the guidance of a doctor.