It’s cold and flu season. Should you take a probiotic?

June 9, 2026 — 5:30pm

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It’s been cold and windy in Melbourne these past few weeks, and I’ve had a niggling virus – the sort where the worst symptoms go away after a few days, but the blocked nose lingers and lingers … not fun!

As the weather closes in and the microbes start to circulate, some of my friends are turning to a class of supplements heavily marketed for their cold-busting properties: probiotics.

A study by Federation University’s Hafiz Ahmad and colleagues crossed Examine’s desk a few weeks ago: they randomised 118 kids across Victorian childcare centres to get either a probiotic or a placebo over six months.

They found no difference in respiratory tract infection rates – but a significant drop in dreaded gastro infections over the last three months of the study.

Interesting! But that’s one study – and, as we’ll see, there is voluminous literature on probiotics. What’s the bigger picture?

Humans have long sought out bacteria – to ferment milk into yoghurt, wheat into bread, grapes into wine. The Romans recorded barbarians using soured milk to treat diarrhoea; the Turks used yoghurt (a Turkish word deriving from yoğuşmak, to curdle) to treat gastrointestinal problems.

Around the turn of the 19th century, scientists started to isolate bacteria in the human gut, and the field of probiotics was born.

Unfortunately, and as is often the case, the supplement industry has run far ahead of the science, selling probiotics........

© WA Today