Vitamin B can be taken for a long time, basically there are no side effects, because vitamin B is water-soluble, the body can not manufacture and synthesis, in the body only a few hours, will be eliminated with urine, will not cause a large number of accumulation in the body poisoning situation, so if the intake of food can not meet the body needs, can be supplemented by other means to vitamin B. Vitamin B is an essential trace element for the human body, lack of vitamin B can cause gastrointestinal diseases, stomatitis, skin roughness, memory loss, etc., if a balanced diet can get enough vitamin B from food, no need for additional supplementation, such as yeast, animal liver, cereals, eggs, etc. are rich in vitamin B, as long as a balanced diet can meet the needs of the human body a day.