A causative role of bacteria in Crohn’s disease (CD) has been surmised for a long time. Only in recent years however has there been a large body of evidence from genetic and bacteriological studies indicating that the intestinal flora is the essential factor in driving the Crohn’s inflammatory process in genetically susceptible individuals.^1–5

The therapeutic arsenal for treating CD assumes the correctness of the above hypothesis. Thus immunosuppressors are used to reduce the host response and antibiotics are used to suppress the bacterial flora, with a consequent decreased activation of the gut immune system.⁶ Between the two strategies it should theoretically be better to remove the harmful cause instead of reducing the host defences by inducing a form of immunodeficiency that is susceptible to opportunistic infections.

If the intervention on the gut flora works, substituting antibiotics (which are heavily burdened by side effects) with probiotics is an appealing alternative. Probiotics are defined as a living microbial food ingredient with a beneficial effect on human health⁷; however, the concept that probiotics are a type of long life elixir useful in many pathological conditions needs to be viewed with caution.

In a world medical scenario, where new science develops new drugs and the financial cost increases, natural remedies, relatively cheap and potentially free from side effects, catch the consumer’s attention, thereby possibly biasing medical judgement.

To date, diverse probiotics, …