Gut Feeling

Last month I wrote about why coughs and colds become common companions as autumn progresses. Alongside this rise in respiratory viruses, GP surgeries will tend to see a rise in the number of patients hoping antibiotics might speed recovery. To understand why they often do not, it helps to consider the remarkable ecosystem living inside us.

The human digestive tract contains trillions of bacteria, viruses and fungi collectively known as the gut microbiome. For years we primarily viewed these microbes as threats, but modern science has revealed a more nuanced relationship. Far from being unwelcome guests, many perform useful functions on our behalf.

Some help digest food components that would otherwise pass through unused. Others produce substances that nourish the cells lining the bowel. Perhaps most intriguingly, there is constant communication between the microbiome and the immune system - our gut microbes help regulate many of our body's natural defences.

Like any ecosystem, diversity matters. A thriving meadow is more resilient than a monoculture, and the same principle applies within the gut. The easiest way to encourage this diversity is through a varied diet rich in vegetables, fruit, beans, lentils, nuts and wholegrains. These fibre-rich foods provide sustenance for many beneficial species.

This brings us back to antibiotics. These medicines remain one of the greatest advances in medical history and can be lifesaving when treating bacterial infections such as pneumonia. However, they have no effect on the viruses causing most coughs, colds and sore throats. Antibiotics also do not distinguish between harmful bacteria and the many helpful residents of the gut.

When a GP recommends against antibiotics, it is not because the illness is unimportant, but because they are unlikely to help and may cause unwanted side effects.

Sometimes the best prescription is patience. For most viral infections, fluids, rest and time are all that is required. If symptoms become unusually severe, breathing is difficult, or recovery is not following the expected course, medical assessment is sensible. Otherwise, allow your microbiome to quietly tend to the garden within.

Dr Chris Humphries

Published: Nov 13, 2026