A double-blind crossover trial against placebo was conducted to assess the effects of the GABA derivative, baclofen, on the disabilities due to muscle spasticity in twenty children suffering from cerebral palsy. Baclofen performed very significantly better than placebo in reducing spasticity and significantly better than placebo in allowing both active and passive limb movements to be carried out. Notable improvement was also seen in scissoring. Side-effects were minimal and responded promptly to dose reduction. The evaluation of drug effects on muscle spasticity and the pharmacodynamics of baclofen are discussed. Recommendations are made regarding dosage of baclogen in childhood.