The paper summarizes the concept of somatoform disorders, which was first introduced in the Diagnostic and Statistical Manual of Mental Disorders in its third edition in 1980. The relevant clinical trials related to this concept are reviewed. On the basis of this experience, the present study discusses methodological requirements for clinical trials, including inclusion and exclusion criteria, measurements of efficacy and safety, and statistical considerations, in the hope that this will stimulate the use of this diagnostic entity in the future.