Reliable data on the psychopharmacotherapy of somatoform disorders (SDs) are scanty because of patients' poor psychopathological awareness and compliance, the need for combination treatment, and the lack of suitable instruments for clinical diagnosis and assessment. The aim of the present study was to investigate the efficacy and tolerability of low doses of levosulpiride in the treatment of SDs. Seventy-four patients with SDs diagnosed according to ICD-10 and DSM-IIIR criteria by means of the Comprehensive International Schedule for Somatoform Disorders-Somatoform Disorders Schedule (CISSD-SDS) were treated for 4 weeks either with levosulpiride (50 mg b.i.d.) or placebo, under double-blind, cross-over conditions. The clinical evaluation was performed using CISSD-SDS. Side-effects were evaluated using the Simpson and Angus Extrapyramidal Side Effects Scale (EPSE) and specific check-lists for anticholinergic and endocrine side effects. Levosulpiride significantly reduced the number of SD symptoms compared to placebo ( P =0.007) after 4 weeks of treatment. Eighty per cent of positive responses were observed during treatment with levosulpiride in the placebo-levosulpiride sequence; on the other hand, only 44% of positive responses were found during treatment with active compound in the levosulpiride-placebo sequence ( P <0.002). Levosulpiride also determined a more evident reduction of the total number of SD symptoms compared to placebo ( P <0.001). There were no differences in endocrine and anticholinergic side effects between levosulpiride and placebo. In the levosulpiride group, a higher percentage of patients (13.4 vs. 2.8%; P =0.029) showed signs of extrapyramidal system involvement compared to placebo. Levosulpiride appears to be a well-tolerated and effective drug for the treatment for SDs.