AIM: To evaluate the efficacy, safety and effects on changes of T lymphocyte subsets of mycobacterium phlei and cisplatin in treatment of patients with malignant pleural effusion (MPE). METHODS: 62 patients of MPE were randomly assigned to two groups. The test group was treated once a week lasting for 1-3 weeks with NS 20 ml + mycobacterium phlei 8.6 ?g + cisplatin 40 mg, while the control one with NS 20 ml + cisplatin 40 mg only. The efficacy and changes of T lymphocyte subsets before and after therapy were analyzed separately. RESULTS: The overall response rate in the test group was 87.5 %, which meant significantly higher than that in the control group (P