INTRODUCTION: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, affecting over 400,000 patients, and leading to over 200,000 deaths annually. Camptothecin (CPT), is a potent widely used chemotherapeutic drug. It shows a significant antitumor activity against various types of cancer. It inhibits the activity of DNA topoisomerase I enzyme (TOP I) during the S phase of the cell cycle leading to persisting single-stranded DNA breaks. OBJECTIVES: To study the therapeutic efficacy of CPT chemotherapeutic drug against induced oral squamous cell carcinoma (OSCC). Also the study will evaluate the treatment, by the use of proliferative immune-histochemical marker (PCNA). MATERIALS AND METHODS: Squamous cell carcinoma will be chemically induced in thirty Syrian hamsters. Then they will be divided into two groups, 15 per each. One group will be treated with CPT, The other group will be treated with saline as negative control group. RESULTS: CPT treated animals showed significant results over the control group. CONCLUSIONS: CPT induced apoptosis in tumor cells and enhanced survival rates in comparison to control group < /p>