This study makes an observation over the objective response rate of autologous erythrocytes derived microparticles packaging methotrexate peritoneal perfusion and systemic therapy combination in the treatment of malignant ascites. All the participants will randomly receive the treatment of autologous erythrocytes derived microparticles packaging methotrexate peritoneal perfusion and systemic therapy combination or convention drugs peritoneal perfusion and systemic therapy combination.

As a drug carrier, erythrocytes have their own advantages, such as high biocompatibility, high immune compatibility, simple structure and easy access. In this study, microparticles released from erythrocytes are used as the carrier of chemotherapy drugs and effectively kill tumor cells in malignant ascites. These microparticles can easily reach the tumor site and bring the drug into tumor cells, which can overcome the two main problems in normal chemotherapy: damage to normal cells and drug resistance of tumor cells.

Inclusion Criteria:

• 18 and ≤ 80 years of age
• Histological confirmed gastric cancer, colorectal cancer, or ovarian cancer, tumor cells were detected by exfoliative cytology of peritoneal effusion, refractory or recurrent ascites of ovarian cancer were required, other kinds of cancer were not limited
• Vital signs were stable, Karnofsky ≥ 70, life expectancy of more than 3 months
• The hematopoietic function of bone marrow was normal without bleeding tendency (INR < 1.5), blood routine examination: HGB ≥ 90 g/L, WBC > 4.0 × 10^9/L (NEU ≥ 1.5 × 10^9/L), PLT ≥ 80 × 10^9/L
• Liver function: STB ≤ 1.5 ULN, AST and ALT≤ 2.5 ULN (if the abnormity of liver function was mainly caused by tumor invasion, AST and ALT ≤ 5 ULN), ALP ≤ 1.5 ULN
• Renal function: BUN and Cr ≤ 1.5 ULN, CCr ≥ 50mL/min
• ECG and blood glucose level were normal
• Patients or family members agreed to participate in the study and signed informed consent
• No other serious heart and lung disease, etc.

Exclusion Criteria:

• Pregnant or lactating women
• Allergic constitution and multi-drug allergy
• Serious heart, lung, liver and kidney dysfunction, decompensated heart, lung, kidney, liver and other major organs dysfunction or failure, poor blood glucose control, chemotherapy intolerance, combined intestinal obstruction
• Concurrent severe infection
• HIV positive, HBsAg and HBV DNA copy number positive (quantitative detection ≥ 1000 cps/mL), chronic hepatitis C blood screening positive (HCV antibody positive)
• Cognitive impairment or poor chemotherapy compliance determined by investigator
• Less than 4 weeks from the last clinical trial
• Unsuitable for clinical trials determined by investigator