The aim of this retrospective study is to review and describe the safety and the efficacy of recombinant human interleukin-11 (I) i (Baijieyi), using information already recorded in 20 medical records, The time periods include May 8th of 2008 to december 31st of 2016.

Inclusion Criteria:

1. prescriptions explicitly given to the injection of Baijieyi;
2. confirmed by histopathological or cytological examination of malignant tumors and chemotherapy;
3. treatment: platelet count had reached below 75×10^9/L after the treatment of chemotherapy and before using Baijieyi; prevention: patients with chemotherapy at the beginning of the preventive administration of BaiJieyi, and chemotherapy is same with previous cycle;
4. male or female, aged 18-85 years;
5. The main research information required is complete.

Exclusion Criteria:

1. using other platelets of chemicals or biological products in the in the chemotherapy cycle used Baijieyi;
2. using drugs which can cause thrombocytopenia in the in the chemotherapy cycle used Baijieyi;
3. bone marrow dysfunction or bone marrow involvement;
4. There are other causes of thrombocytopenia, such as aplastic anemia, acute leukemia, radiation sickness, immune thrombocytopenic purpura, and hypersplenism, in the course of the use of Baijieyi.

A total of 20 clinical centers: subjects.who have received one or more injections of Baijieyi for treatment or prevention of chemotherapy-induced thrombocytopenia