Toluidine blue is a metachromatic dye, used to identify Premalignant and Malignant lesion of oral cavity. It is safe and economical to use while it selectively stains DNA and RNA in cancer cells and hence delineates them. In outpatient clinics, its role as a screening tool is well established but its use to assess intraoperative tumor margins of oral cavity cancer is yet to be proven. It is therefore, necessary to identify the true potential of this dye by performing such studies.