First Signs of the Stomach Bug

Gastroenteritis irritates the stomach and bowel, commonly after an infection. Symptoms may appear together or develop over a short period. Vomiting and diarrhoea can remove fluid and salts, leading to dehydration. Warning clues include a dry mouth, unusual thirst, dizziness, very dark urine or passing urine less often. Similar symptoms can follow food irritation or another illness, so the pattern and exposure history matter.

Take frequent small sips of water or an oral rehydration drink, especially after vomiting. Once tolerated, choose simple foods and return gradually to your usual diet. Rest, wash hands carefully and avoid preparing food for others while unwell. Do not give children anti-diarrhoea medicine without professional advice. A GP can assess persistent symptoms or suspected gastroenteritis.

Seek urgent care for severe dehydration, fainting, confusion, severe or localised abdominal pain, blood in vomit or stool, or inability to keep fluids down. Get medical advice promptly for a young child, an older adult, pregnancy or a long-term condition when vomiting or diarrhoea is significant.

Ask whether you need testing, how to replace fluids safely, which medicines to avoid, and what symptoms would suggest dehydration or another cause.