Radiotherapy can cause radiation stomatitis, which is commonly seen in patients undergoing radiotherapy for head and neck tumours. Acute radiation stomatitis can be characterised by mucosal congestion, redness, swelling, erosion and ulceration, covered with a pseudomembrane, bleeding easily and painful to the touch. Acute lesions of radiation stomatitis usually heal gradually 2-4 weeks after the end of radiotherapy or 1-2 weeks after regular treatment.