A large number of studies have been published on the value of probiotics in treating or preventing diarrhoea. Although no definitive conclusion has been reached, the balance of opinion appears to be that probiotics can be beneficial, reducing the incidence of diarrhoea in certain circumstances but not preventing it or curing it completely.
From my reading of the evidence, it would seem that the best use for probiotics is in preventing diarrhoea associated with antibiotic use. Probiotics also appear to be reasonably successful in treating paediatric diarrhoea, although only to the extent of reducing duration by about a day or two. Similarly, probiotics appear to reduce duration of acute diarrhoea in adults by a few hours to about a day.
Results have been conflicting in relation to traveller's diarrhoea, but some trials have shown a reduction in incidence. It seems that the effect of probiotics on traveller's diarrhoea may depend on the bacterial strain used and the destination of the traveller.
My opinion, from reviewing the evidence, is that:
- there is no harm in recommending probiotics as there appear to be no reports of adverse effects in normally healthy people
- they may be useful in preventing antibiotic-associated diarrhoea if given throughout the course and for a week afterwards
- there is no harm in recommending them to prevent traveller's diarrhoea, when they may (or may not) be helpful
- there is little point in taking probiotics continuously to prevent acute diarrhoea, because this should be an infrequent occurrence that is probably more effectively avoided by good food hygiene at home and judicious choice of places to eat (eg, restaurants) or buy pre-cooked food (eg, take-aways).
