Cang Er Zi is best used for treating external wind-cold or nasal abyss (mainly manifested as foul nasal mucus, the amount of which cannot be wiped clean) and runny nose, and is generally not used for treating lumbago. Cang Er Zi is a flavor of antidote, with wind-cold, through the nose, the efficacy of wind-dampness, clinically used for wind-cold cold, nasal abyss, wind-dampness paralysis, wind rash, itching, scabies and leprosy. Cang Er Zi is toxic, overdose will lead to poisoning, triggering vomiting, diarrhea dizziness, drowsiness and other symptoms. Cang Er Zi can dissipate qi and blood, so patients with blood deficiency headache should not take it. It is recommended to take under the guidance of a doctor to avoid adverse reactions. If the patient has symptoms of back pain, it is recommended to go to the hospital for examination and comprehensive treatment, avoid unauthorized use of medication to avoid adverse reactions or delayed condition.