Bifidobacterium animalis, a gram-positive, anaerobic, rod-shaped bacterium, is commonly found in the large intestines of most mammals, including humans. It belongs to the Bifidobacterium genus and has two subspecies: Bifidobacterium animalis subsp. animalis and Bifidobacterium animalis subsp. lactis. Both old names, B. animalis and B. lactis, are still used on product labels, especially in probiotics. These strains are frequently used for their potential health benefits.