The efficacy of intrathecally administered baclofen was demonstrated in three patients with different types of muscular hypertonia (supraspinal rigidity, spasms shortly after spinal trauma, spasms for many years induced by multiple sclerosis) using integrated electromyography. Reduction of muscular electrical activity was accompanied by clinical improvement during long-term infusion via an implanted pump. The three patients have been observed for more than 1 year, during which time the antispastic activity of intrathecally infused baclofen has remained stable. Intrathecal application of baclofen may be considered as a possible alternative to surgery.