The aim of this study was to assess trihexyphenidyl in reducing overall dystonia, improving upper limb function, and achieving goals in children with dystonic cerebral palsy. A randomized, double-blinded, placebo-controlled, crossover trial was conducted with 16 participants at a tertiary children's hospital. Assessments were performed at baseline, week 12, and week 28. The primary outcome measure was the Barry-Albright Dystonia scale for global assessment of dystonia. Secondary measures included the Quality of Upper Extremity Skills Test, Canadian Occupational Performance Measure, and Goal Attainment Scale. A total of 14 children (88%) completed the study. Mean baseline Barry-Albright Dystonia score was 18.4 (95% confidence interval, 15.5-21.2). There were no significant treatment effects as measured by change in outcome scores. There were significant order effects for both the Goal Attainment Scale and performance aspect of the Canadian Occupational Performance Measure. Side effects were common. Larger experimental trials with more narrowly defined functional levels are indicated.