Head and neck cancer is a major health problem. Oral cancer is increasing in Indian subcontinent mainly due to lack of hygiene, tobacco use, chewing tobacco, smoking, and many other factors. Radiation therapy is the most common form of treatment along with surgery and chemotherapy. There are 2 types of complication that occurs during and after radiotherapy, that occur because of effects on normal tissue. Radiotherapy-induced effects occur on the oral mucosa salivary glands, bone, teeth, and musculature of face and neck. These complications needs special attention for their prevention and treatment, Preradiotherapy evaluation and disease stabilization are necessary in every patient, counseling of patients before during and after radiotherapy is important to help them become aware of several oral complications and their prevention.