Botulinum toxins (BTX) have revolutionised the management of focal post-stroke spastic hypertonia. Published literature has supported the efficacy and safety of BTX in reducing spastic hypertonia but has not convincingly demonstrated the ability to enhance function. While clinicians and stroke survivors have reported impressive clinical outcomes, randomised, controlled trials (RCTs), have demonstrated only significant improvement in muscle tone but not functional changes. This paper will review the evidence supporting the efficacy of BTX for spastic hypertonia and discuss current clinical practice.