Inclusion Criteria:

• Children aged 0 to 18 years with hematological malignancies.
• Children with high-risk neutropenic fever, namely children with blood malignancies induction phase ALL, consolidation phase ALL, reinduction phase ALL, relapse ALL; meningeal ALL, AML, and NHL, diagnosed by a competent pediatrician on duty.
• Consent from parents to be included in the study.

Exclusion Criteria:

• Children with malignancies but accompanied by comorbidities (HIV infection, septic shock).
• Allergy to ciproloxacin or ceftazidime.
• Fever associated with blood transfusion reactions.
• Receiving other antibiotics since 72 hours before being included in the study, except for cotrimoxazole prophylaxis for the prevention of Pneumocystis carinii pneumonia, and ciproloxacin prophylaxis in AML.
• Children with blood malignancies who have impaired renal function (serum creatinine ≥ 1.5 times the upper normal limit) and impaired liver function (SGPT > 5 times the upper normal limit).