Potential advantages of intramuscular botulinum toxin for the treatment of spasticity include the lack of sensory effects, ability to target specific muscle groups, ability to weaken muscles in a graded fashion and absence of caustic chemicals such as phenol. We describe the use of botulinum toxin for the treatment of severe lower extremity spasticity in two subjects with multiple sclerosis. Both subjects showed an improvement in spasticity, as measured by the modified Ashworth scale, and in functional status. Both subjects exhibited reductions in muscle tone not only in injected muscles, but also in noninjected muscles in the region. These more distant clinical effects have not been emphasized in previous studies after therapeutic injections of botulinum toxin. Further research is needed to clarify the cause and prevalence of these regional motor effects, as well as to further examine the safety and efficacy of botulinum toxin for spasticity treatment.