Prognosis of oropharyngeal squamous cell carcinoma depends on early diagnosis, despite advanced surgical techniques, the 5-year survival rate remains ~40-50%. Unfortunately, it is usually detected when it becomes symptomatic. This requires treatment which gives rise to a high rate of morbidity and mortality and, furthermore, early detection of oro-pharyngeal pre-malignant lesions is important to improve the survival rate and quality of life. Since dysplasia and in situ carcinoma contain much more DNA and RNA than the normal surrounding epithelium, the use of in vivo staining, by means of toluidine blue dye, is based on the fact that it is an acidophilic dye that selectively stains acidic tissue components such as DNA and RNA. Toluidine blue staining is considered to be sensitive in identifying early oro-pharyngeal premalignant and malignant lesions. In the present study, the use of toluidine blue staining was taken into consideration to identify clinically doubtful oro-pharyngeal lesions and to compare toluidine blue stain and with the histological evaluation.