Probiotics which means "for life" have been used for centuries as natural components in health promoting foods. Probiotics are live microbial feed supplements which beneficially affect the host animal by improving its microbial balance in intestines. The large intestine of humans contain balanced and complex micro flora which prevents infection and has a positive effect on nutrition. Diet changes or stress or antibiotic therapy can upset this microbial balance, making the host susceptible to disease. Following are the potentially beneficial medicinal use of probiotics: Managing lactose intolerance, Prevention of colon cancer, Cholesterol lowering, lowering blood pressure, improving immune function and preventing infections, peptic ulcers, reducing inflammation.
Sources are: Curd is rich in probiotics. Other foods like idli, dosa, dhokla etc where fermentation is part of cooking procedure, may also be good source of probiotics.