Miguel Freitas, PhD, medical marketing manager for Dannon Co., says the benefits associated with probiotics are specific to certain strains of these "good" bacteria. Many provide their benefits by adjusting the microflora (the natural balance of organisms) in the intestines, or by acting directly on body functions, such as digestion or immune function. (Keep in mind that the only yogurts that contain probiotics are those that say "live and active cultures" on the label.)