Table 6. World Health Organization Oral Toxicity Scale (WHO OTS)

Scale Score	Symptom
Scale 0	No mucositis
Scale 1	Soreness and erythema
Scale 2	Erythema and ulcers, patient can swallow solid food
Scale 3	Ulcers with extensive erythema and inability to swallow solid food
Scale 4	Mucositis so extensive that oral alimentation is not possible, including swallowing liquids