Contraindications to vitamin B are currently unclear. However, it should be noted that patients with hepatic or renal insufficiency and allergies should use this drug with caution. When used for daily supplementation and prophylaxis, the lowest dosage is appropriate. For therapeutic use, consult a physician for specific dosage. Vitamin B is mainly used for the prevention and treatment of malnutrition, anorexia, athlete’s foot, pellagra, etc. caused by B vitamin deficiency. After use, patients may experience adverse reactions such as skin flushing, itching, yellowish urine, headache, dizziness, blurred vision and abdominal pain. Adverse reactions such as irritability, fatigue, and loss of appetite may occur when large doses are taken. Vitamin B contraindications are currently unknown. Precautions are: When used for daily supplementation and prophylaxis, the lowest dosage is appropriate. When used for therapeutic purposes, the physician should be consulted for specific dosage. Patients with hepatic or renal insufficiency, and patients with allergies should use this drug with caution. If you need to use this kind of drug, you need to use it under the guidance of a doctor, do not use it blindly on your own, so as not to cause adverse consequences.