Thirty-three patients with an arthrographically documented anterior disk displacement without reduction were randomly assigned to be treated with upper joint space lavage or to serve as controls in an 8-week clinical trial. Pain was evaluated by the patients on a visual analog scale at rest and after chewing gum. The clinical examination followed a standardized protocol. Improvements in pain and mouth opening were found in both the lavage and control group after 8 weeks, but there were no statistically significant differences between the treatment and control groups. It was concluded that upper joint space lavage after arthrography seems to be ineffective to decrease pain and to increase mouth opening in patients with anterior disk displacement without reduction.