Reported here is the therapeutic efficacy of Tiapride with 10 10- to 17-yr.-old patients afflicted with severe stuttering problems. During the 20-wk. open, controlled study (baseline, low dose of Tiapride, high dose of Tiapride, follow-up observation without medication) the stuttering in various speech situations decreased markedly. No substantial change in different parameters of acoustic analysis and psychopathological characteristics accompanied the reduction in stuttering when group data were compared although positive effects concerning these variables could be seen in some cases. Several conclusions based on these results are presented. One assumed effect of the medication is improvement of central nervous regulatory mechanisms of speech motor coordination. Further, the value of the medication Tiapride in comprehensive stuttering therapy is discussed.