b2 refers to vitamin B2, there are no obvious contraindications except for allergic people to use with caution. Vitamin B2 mainly for the patient’s body to replenish a large number of vitamins, generally and other drugs do not have obvious conflicts, and will not produce adverse reactions, but some allergic people, very easy to take vitamin B2, and nausea, vomiting, skin rashes, fever, and other allergic reactions, and the serious cases may even shock, palpitations, etc., therefore, for allergic people should be careful to use vitamin B2. In addition, in daily life, patients are advised to eat more vegetables and fruits, and consume some fish, shrimp and other foods rich in vitamin B2, supplementing vitamin B2 through food to minimize the lack of vitamin B2. All medications should be used under the guidance of a doctor, avoid self-medication.