Probiotics are live, microbial food supplements that benefit the host animal by 
improving intestinal microbial balance. Their major role in preventing and 
treating gastrointestinal disease appears to be from their effect on the immune 
process, protection against abnormal invasive bacteria, and in the production of 
short-chain fatty acids from starch and non-starch polysaccharides. Probiotic 
microorganisms are administered in food supplements and yogurts. They are also 
now sold in the form of capsules and powders. There is great variation in the 
microorganisms in the various supplements. It is important to understand that 
all probiotic products are different. Some contain a single organism and others 
contain multiple organisms. Therapeutic results have been achieved with various 
probiotics in different diseases. In the treatment of inflammatory bowel 
diseases (IBD), success has been reported with Escherichia coli Nissle strain in 
ulcerative colitis, and with a multiple organism product, VSL#3 (VSL 
Pharmaceuticals, Fort Lauderdale, FL), in Crohn's disease and pouchitis. Initial 
reports in irritable bowel syndrome (IBS) have resulted in encouraging results 
with the use of E. coli Nissle strain, and recently with multiple organism 
probiotic supplements. However, caution must still apply to the use of 
probiotics in IBD and IBS because the reports and the number of patients treated 
are limited.