Left trigeminal neuralgia may be primary or secondary, such as caused by intracranial organic lesions. 1. Primary trigeminal neuralgia: the etiology is still unclear, but in recent years, it has been clinically found to be related to atherosclerosis of the oxygen-supplying nerves, distortion of the arteries, thickening of the meninges, and arterial compression on the nerve roots. 2. Secondary trigeminal neuralgia: usually there is a clear cause, such as tumor at the base of the skull, meningitis, brainstem infarction, multiple sclerosis, etc., which invades the sensory nerve root of the left trigeminal nerve and causes pain, mostly accompanied by the loss of the function of the left trigeminal nerve itself and the damage of the neighboring structures. Trigeminal neuralgia is firstly treated with medication, such as carbamazepine, and then radiofrequency thermo-coagulation or surgery if the medication has no obvious effect. In addition, if the trigeminal neuralgia is caused by a tumor at the base of the skull, meningitis and other primary diseases, the patient needs to treat the primary disease to relieve the symptoms. If trigeminal neuralgia occurs on the left side, the patient should consult the doctor in time, improve the relevant examination and actively treat it, do not blindly self-medication.