Vitamin B, which is classified as water-soluble B by McCollum in early period, is the indispensable material in vivo to convert saccharide, fat and protein to heat. Vitamin B includes thiamin, vitamin B2, niacin, vitamin B6, pantothenic acid, biotin, folate, and vitamin B12. They can be used as drugs and play an important role in the treatment of diseases, like neuritis, beriberi, angular stomatitis, fetal anomaly, etc. This type of vitamins has totally different chemical structures, but most of them are from plant extracts. Vitamin B could promote oxygen utilization in vivo to improve oxygen levels in many tissues, and it also could help organism in removing toxins. Vitamin B deficiency could cause indigestion, constipation, halitosis, and so on.