Objective: To observe the effect of Lianbai liquid (连柏液) in prevention and treatment of acute radiation dermal injury. Method: From May 2000 to December 2005, 126 cancer patients were randomly divided into a prevention group of 75 cases given extally topical application of Lianbai liquid since the first radiotherapy, and a control group Ⅰ of 51 cases given only advice after radiotherapy; while the other 92 cancer patients who had already had grade Ⅲ acute radiation-induced dermal injury were randomly divided into a treatment group of 54 cases treated by extally topical use of Lianbai liquid, and a control group Ⅱ of 38 cases treated by topical use of norfloxacin. Clinical evaluation was carried out according to the CTC.V2.0 standard stipulated by NCI for classifying acute radiation dermal injury. Results: The incidence of skin reaction was 32.0% in the prevention group and 92.2% in the control group Ⅰ, with an obvious difference between the two groups (χ2=54.163, P＜0.01). Mild radioactive reaction (grade Ⅰ and Ⅱ) was 28.0% (21/75) in the prevention group and 70.6% (36/51) in the control group Ⅰ, with a remarkable difference between the two groups (χ2=22.226, P＜0.01). The effective rate for grade Ⅲ dermal injury was 92.6% (50/54) in the treatment group and 65.9% (25/38) in the control group Ⅱ, with a remarkable difference between the two groups (χ2=6.018, P=0.024). The wound-healing time was 11.07±2.21 days in the treatment group and 18.08±1.76 days in the control group Ⅱ, with a remarkable difference between the two groups (u=16.932, P＜0.01). Conclusion: Lianbai liquid can effectively prevent the radiation dermatitis, and treat grade Ⅲ acute radiation dermal injury with obvious curative effect.