The World Health Organization classifies pain into five levels. Level zero is no pain. Level one is mild pain that does not require medication. Level two is moderate pain that requires medication. Level three is severe pain that necessitates medication. Level four involves severe and intense pain, often accompanied by changes in vital signs such as blood pressure, pulse, and respiration. Trigeminal neuralgia is a type of severe pain that occurs repeatedly in the trigeminal nerve area. It is recognized globally as one of the most painful diseases, often referred to as the "world's greatest pain" and "the cancer that does not kill." Patients often live in a state of feeling better off dead, which indicates the extreme level of pain associated with this disease. The pain level for this condition is classified as level four, the highest level.