Abstract: Purpose: To observe the radiosensitization and side-effects in the treatmentof malignant tumors. Materials and Metheds: From October, 1994 to February,1995, 52 pattens were treated with radiotherapy and Iq7611. In the observed group,Iq7611 was taken orally, 120mg a time, 2 times a day, 2 hours before and after radiotherapy. In the control group, the patients were treated with radiontherapy alone. Results: The instant result of primary and metastatic foci and the side-effects were classified according tO the observed items of UICC and the classification criteria of Poisonous and side effects recommended by WHO. The instant result was better in the Observed group than in the control group, but the Poisonous and side effects were nothigher. Conclusion: The results show that the Iq7611 has radiosensitization. The poisonous and side effects were well tolerated. The clinical study should be done further.