Cancer is a genetic disease, and one of the main public health problems. Cancer treatments (chemotherapy and radiotherapy) have some side effects, such as mucositis, which is the inflammation of the oral mucosa, and which generates a series of discomforts, sometimes milder, sometimes more severe. One of the treatments indicated for mucositis is low-level laser therapy, which acts to reduce symptoms. The purpose of this article is to describe four protocols of laser therapy, which were applied at Hospital Santa Rita de Cássia — Vitória, and also to discuss the results that were satisfactory.