What should you know about effects of stomach flu?

Gastroenteritis irritates the stomach and intestines. Nausea, vomiting, watery diarrhoea, abdominal pain, fever and loss of appetite can occur together. Rotavirus infection is one possible cause, although other viruses, bacteria, parasites or contaminated food can also be responsible.

The main concern is loss of water and body salts. This can produce thirst, dry mouth, dizziness, headache, weakness and dark or infrequent urine. Children, older adults and people with long-term illnesses can become unwell more quickly. Symptoms may settle with supportive care, but worsening fluid loss needs medical assessment.

Take small, frequent sips of water or an oral rehydration drink. If vomiting makes drinking difficult, pause briefly and restart with tiny amounts. Eat when able, choosing simple foods that you tolerate, and rest. Wash hands carefully and avoid preparing food for others while infectious symptoms continue.

Do not take antibiotics unless prescribed, because many cases are viral. Ask a pharmacist or clinician before using anti-diarrhoeal medicines, especially for a child or when there is fever or blood in the stool.

Get urgent help for confusion, fainting, severe abdominal pain, blood or black material in vomit or stool, breathing difficulty, inability to keep fluids down or very little urine. Contact a clinician promptly for persistent vomiting or diarrhoea, a high temperature, signs of dehydration, or symptoms in a young child, older adult or medically vulnerable person.

How can I replace fluids safely? Do I need testing for infection, and which medicines should I avoid? What signs would mean dehydration is developing, and when can I return to work, school or preparing food?