Bifidobacterium lactis subspecies. Hanson BB- 12? Bifidobacterium strain is the most fully studied strain in the world, which has been described in more than 300 scientific publications, among which 130 publications are related to human clinical research. It is the only Bifidobacterium strain with complete gene sequence. Hanson BB- 12? The health care function of this compound has been verified in many clinical studies on gastrointestinal health and immune function.