Abstract: Objective To observe the curative effects and adverse reaction about lobaplatin used for intracavitary instillation on malignant pleuroperitoneal cavity hydrops. Methods Thirty-two patients with malignant pleuroperitoneal cavity hydrops，locationed by B-ultrasonic wave and given puncturing and inserting catheter，were given lobaplatin for intracavitary instillation，once a week，for 2 weeks，4 times at most. The curative effects and toxicity were evaluated after 2 weeks. Results Thirty-two patients were given intracavitary instillation for at least 2 times. Of all the patients, complete response（CR） was observed in 9 patients（28.1%）, partial response in 15 patients（46.9%）, NS in 8 patients（25.0%）. The response rate（RR） was 75.0%. The RR of pleural effusion and seroperitoneum was 80.0% and 66.7%, respectively. The toxicity mainly included chest or abdominal pain，fever，low platelets and digestive tract reaction. Conclusion Lobaplatin is effective used for intracavitary instillation on malignant pleuroperitoneal cavity hydrops with mild adverse reaction，so it is worth to be popularized.