Treatment of Oral Premalignant Lesions With 5-ALA PDT

Inclusion Criteria: * At least one grossly visible premalignant lesion (i.e. leukoplakia or erythroplakia) in the oral cavity or oropharynx, with a confirmed diagnosis of leukoplakia with or without dysplasia,measuring ≥ 10 mm in diameter. * Informed of alternative treatment methods including watchful waiting, laser ablation, or surgical resection. * Eligible for long-term follow-up for at least one year and be able to tolerate biopsies. * Subject has signed an informed consent. * Subject is between the ages of 18 - 80 years of age. * Male or Female * Zubrod performance status of 0 or 1 at screening. See Appendix A Exclusion Criteria: * Known sensitivity to porphyrins or photoactive medications - See Appendix B * Invasive carcinoma of the lesion as demonstrated by biopsy. * Subjects with inherited or acquired blood clotting defects * Women who are breast feeding, have a positive (+) urine pregnancy test, or refuse to use 2 effective means of contraception during drug exposure and up to 48 hours after. * Subjects with porphyria * Life expectancy less than 12 months * Inability or unwillingness of subject to give written informed consent