Objective To further observe the effect of botulinum toxin A(BTXA) treatment on hemifacial spasm(HFS) patients and to investigate the value of double stimulation of blink reflex(BR) before and after BTXA injection. Methods Among 134 cases of HFS treated by local injection of BTXA, the changes of BR in 42 cases was recorded before and after the injection. Results Of totally 134 treated cases, 60 (44 8%) cases were completely relieved and the rest 74 (55 2%) cases were obviously improved after treatment, with an effective duration of 16 5?5 7 weeks.In 42 patients with determination of BR value,before injection the latency of R 1, R 2, R' 2 of the affected side showed within normal limit.The interval of R 2 was shorter and the amplitudes of R 1,R 2,R' 2 were higher .After injection , the R 1 disappeared in 7 patients,and R 1,R 2,R' 2 all disappeared in 5 patients,for the rest 30 patients,the latency of R 1,R 2,R' 2 was prolonged slightly,but showing no apparent differences The amplitudes of R 1,R 2 and R' 2 were lowered significantly ( P