IBS is considered a syndrome defined as a group of symptoms, without inflammation. An examination of the colon does not normally show any sign of disease or abnormality. If probiotics are being tried for IBS, the BNF advises that the microbe(s) should be used for at least four weeks while monitoring the effect.28,29

Inflammatory bowel diseases (IBD) involve intestinal inflammation with potentially permanent harm and increased colon cancer risk.28

Dysbiosis has been shown in people with Crohn’s disease where levels of bacteria species involved in producing butyrate are below levels in the general population. Their relatives, unaffected by Crohn’s, also showed dysbiosis involving increased levels of bacteria capable of breaking down mucin. Clostridium comes interacting with the host’s immune system may also affect the severity of Crohn’s disease.28,30

While there is a microbial element in Crohn’s, the evidence is very uncertain about probiotics inducing remission in Crohn’s disease, and there is as yet no evidence to indicate they have a beneficial effect in maintaining remission. Gastroenterologists, however, consider probiotics can be as effective as standard approaches to active ulcerative colitis, with possibly better response and remission rates in mild to moderate cases.3,32,32