The purpose of the study was to determine if toluidine blue application and counter staining with Logul's iodine would aid in diagnosis of oral dysplastic or malignant lesions. The sensitivity, specificity, and predictive values were studied. Routine use of these tissue stains was found to be sensitive and specific. The use of stains provided better demarcation of oral squamous cell carcinoma and dysplastic changes and assisted in site selection for diagnostic biopsy. The use of toluidine blue and Lugol's iodine can assist in assessment of patients at risk of developing malignant disease and those with lesions that are clinically suspect of dysplasia or malignancy.