Probiotics have been perceived as a solution to many of the life style related problems. In modern era the quality of water and food supply may affect the intestinal micro flora. Chlorinated water and preservatives added to foods may lead to an alteration in the normal micro biota of intestine. Probiotics, however, lead to reversal of this altered microbial picture back to normal. They tend to maintain the delicate balance exiting between the gastro intestinal tract and the immunological system of the body. Whenever this balance is disturbed, a disease develops. Probiotics competitively inhibit the over stimulation of immune system by pathogenic bacteria by adhering themselves to the gastro intestinal mucosa in place of pathogenic bacteria and thus inhibiting their colonization. They have proved to be beneficial in the case of allergies/eczema, diarrhoea, hyperlipidaemia, Acquired Immune Deficiency Syndrome, liver cirrhosis, gastric ulcer, hypertension, inflammation, arthritis, inflammatory bowel disease, peptic ulcer and cancer etc. It is also beneficial in case of antibiotic resistance or antibiotic associated side effects. The present review deals with the updated information about the role of probiotics in health and disease.