What should you know about stomach flu in winter?

Despite its nickname, stomach flu is not influenza. Viruses are a common cause, and illness can pass between people through contaminated hands, surfaces, food or close contact. Winter gatherings and time spent indoors can make these routes easier, so handwashing and staying home while unwell are useful precautions.

Gastroenteritis often starts with nausea, vomiting or loose stools. Abdominal pain or cramping may occur, and some people develop fever, tiredness or reduced appetite. Symptoms can vary between family members, even after the same exposure.

The main concern is fluid and salt loss. Repeated vomiting or diarrhoea can leave the mouth dry and urine darker or less frequent. Infants, older adults, pregnant people and anyone with a long-term condition may become unwell from fluid loss more quickly.

Take frequent small sips of water or an oral rehydration solution. If vomiting makes drinking difficult, pause briefly and try again with smaller amounts. An oral rehydration solution can replace water and salts more effectively than relying on very sugary drinks alone.

Rest, and eat small plain meals when your appetite returns. Avoid preparing food for other people while you have symptoms. Wash hands with soap and water after using the toilet and before eating; clean frequently touched bathroom surfaces, and do not share towels.

Do not give anti-diarrhoeal medicines to a child without medical advice. Ask a pharmacist or clinician before taking symptom medicines if you are pregnant, have kidney disease, take regular medicines, or see blood in the stool.

Seek urgent help for severe or worsening abdominal pain, confusion, fainting, trouble breathing, blood in vomit or stool, or an inability to keep fluids down. These signs can indicate a complication or a different illness that needs prompt assessment.

Contact a clinician if you have signs of dehydration such as very little urine, marked dizziness, unusual sleepiness or a very dry mouth. Get advice sooner for a baby, an older adult, pregnancy, a weakened immune system or a significant long-term illness. A clinician can assess the cause and decide whether testing or treatment is needed.

Ask: Could my symptoms be gastroenteritis or another condition? How much should I drink, and is oral rehydration suitable for me? Which medicines should I pause or avoid while I am vomiting or having diarrhoea? What warning signs mean I should return urgently?