The present invention provides a therapeutic drug that is useful for levodopa induced dyskinesia in Parkinson's disease. In particular, the present invention provides a composition and method for treating, improving, suppressing the progression, or preventing motor complications associated with levodopa therapy for Parkinson's disease, especially levodopa induced dyskinesia (PD-LID), comprising tandospirone or a pharmaceutically acceptable salt or prodrug thereof, wherein the tandospirone or a pharmaceutically acceptable salt or prodrug thereof is parenterally administered.
