Inclusion Criteria:Meet hemophagocytic lymphohistiocytosis (HLH)-04 diagnostic criteria; patients were diagnosed with EBV associated HLH (EBV-HLH) and lymphoma associated HLH.Age ≥18 years old, gender is not limited. Serum creatinine ≤ 1.5 times normal；NT-proBNP ≤ normal；Informed consent obtained.  -  Exclusion Criteria: Active bleeding of the internal organs or patients with new thrombotic diseases；Allergic to Chidamide and etoposide；Participate in other clinical research at the same time；HIV , HBV and HCV infected patients (HIV antibody positive)；History of QT interval prolongation, atrioventricular block, ventricular tachycardia, coronary atherosclerotic heart disease；Pregnant or lactating women and patients of childbearing age who refuse to take appropriate contraceptive measures during this trial. If the patient was male, he refused to use adequate contraceptive methods or donate semen during the study period and within 3 months after receiving the last cycle of drug study；patients judged by the investigator to be unsuitable to participate in this study.  -