What should you know about a new stomach bug?

A stomach bug usually refers to gastroenteritis, an irritation or infection of the stomach and intestines. It can spread through close contact, contaminated food or water, and shared surfaces. Vomiting and loose stools remove fluid and salts from the body, so dehydration can develop, especially in babies, older adults and people who are already unwell. Appetite may be reduced while the gut settles. Symptoms can overlap with other illnesses, so a clinician may consider the pattern, recent contacts, travel, medicines and existing conditions.

Take frequent small sips of water or an oral rehydration drink; small amounts may be easier to keep down than a full glass. Continue breastfeeding, and offer children their usual feeds when tolerated. Eat light foods when hungry, avoid sharing towels or utensils, wash hands with soap and water, and clean contaminated bathroom surfaces. Rest and monitor urination, alertness, vomiting and stool frequency. Do not start antibiotics or anti-diarrhoeal medicine without advice, because the right choice depends on the cause and the person’s age and health.

Arrange medical advice if fluids will not stay down, diarrhoea is persistent, or there are signs of dehydration such as very little urine, marked thirst, dizziness, unusual sleepiness or a dry mouth. Seek urgent help for severe or worsening abdominal pain, confusion, fainting, blood in vomit or stool, or a very unwell child. Fever with concerning symptoms also deserves prompt assessment. A clinician can assess hydration and decide whether testing or treatment is needed.

Could this be gastroenteritis or another cause? How should I replace fluids for my age or my child’s age? Which medicines should I avoid? What signs mean I should seek urgent help?