OBJECTIVE: The efficacy of Botulinum toxin type A (BoNTA) for the treatment of adult focal spasticity was evaluated using a pooled analysis of individual patient data from five randomised controlled trials (RCTs). The objective of the analysis was to determine an overall estimate of patient response rate across spasticity of different muscles. METHODS: Individual patient data from five double-blind RCTs of BoNTA versus placebo for the treatment of focal spasticity were included in the pooled analysis. The trials were 12-24 weeks in duration and enrolled patients with post-stroke focal spasticity in upper or lower limbs. The primary outcomes in the RCTs were assessed using the Ashworth scale, a five-point grading of muscle tonicity. As muscle hypertonia interferes with movement, a reduction in muscle tone is beneficial. For the pooled analysis, a responder was defined as a patient who obtained a decrease of at least two points in the Ashworth scale measurement of any upper or lower limb muscle, indicating a clinically significant improvement. RESULTS: The results of the responder analysis indicated that 140/271 (51.7%) of patients treated with BoNTA were responders compared to 30/136 (22.1%) of patients treated with placebo, a statistically superior result in favour of BoNTA (risk difference 28%; 95% confidence intervals 18-37%; p <0.001). In addition there were no significant differences between treatment groups in the proportions of patients that discontinued treatment or experienced an adverse event, indicating equivalent tolerability. CONCLUSIONS: The results of this analysis indicate that significantly more patients treated with BoNTA obtained a clinically significant reduction of muscle tone, compared with those receiving placebo. Improvement in tonicity reduces muscle resistance and facilitates the use of physical rehabilitation methods to improve a patient's ability to perform various activities of daily living.