There are two most common types of probiotic species. They are Lactobacilli that are responsible for producing lactic acid and control the population of bad bacteria in the body. Secondly, Bifidobacteria, commonly found in foods and supplements, are essential for supporting immune system, breaking down lactose and limit growth of harmful bacteria in the intestine. Different probiotics have different benefits and one must always consult their health care provider before taking probiotics.