I think I have stomach flu: what should I know?

Stomach flu usually refers to gastroenteritis, an infection or irritation causing vomiting, diarrhoea, nausea and sometimes abdominal pain or fever. It is not the same illness as influenza. The immediate concern is replacing lost fluid and recognising signs of Dehydration.

Gastroenteritis can cause loose stools, vomiting, cramping, Nausea, Fever and Loss of Appetite. Viruses are common causes, but food-related illness, medicines and other conditions can produce a similar pattern. Rotavirus Infection is one possible cause, especially in young children. The amount of fluid lost can matter more than the number of bowel movements, particularly for children, older adults and people with other health conditions.

Take frequent small sips of water or an oral rehydration drink; if vomiting occurs, pause briefly and restart with smaller amounts. Continue light foods as tolerated rather than forcing a meal, and avoid alcohol and foods that clearly worsen symptoms. Wash hands with soap and water, clean shared bathroom surfaces and avoid preparing food for others while unwell. Ask a pharmacist or clinician before using anti-diarrhoeal medicines, especially for children, fever or blood in the stool.

Seek urgent care for confusion, fainting, very little urine, inability to keep fluids down, severe or worsening Abdominal Pain, blood or black stool, vomit containing blood, or a persistent high fever. Get medical advice early for infants, frail older adults, pregnancy, diabetes, kidney disease or a weakened immune system. A GP can assess dehydration and consider causes when symptoms are prolonged or unusually severe.

How can I replace fluids safely? Could my medicines or another illness be contributing? Do I need testing? Which foods, drinks or medicines should I avoid? When can I return to work, school or food preparation?