Causes of sickness and diarrhoea

Gastroenteritis can cause sudden vomiting, loose stools, cramps and sometimes fever. Food Poisoning may begin after contaminated food and can affect other people who ate the same meal. Food Intolerance may cause repeated symptoms after a particular food without the pattern of an acute infection. Ongoing diarrhoea, abdominal pain, weight loss or blood in the stool needs assessment for conditions such as Coeliac Disease or Crohn's Disease. Giardiasis is another possible cause after exposure to contaminated water or food. Hyperthyroidism can sometimes be associated with frequent bowel movements and other body changes.

Take frequent small sips of water or an oral rehydration drink. When you can eat, choose simple foods and avoid alcohol, very fatty meals and foods that clearly worsen symptoms. Wash hands with soap and water, clean toilet surfaces and avoid preparing food for others while unwell. Do not use anti-diarrhoeal medicine if you have blood in the stool or a high fever without medical advice.

Get urgent help for severe dehydration, fainting, confusion, severe or localised abdominal pain, blood or black stool, vomit containing blood, or inability to keep fluids down. Contact a clinician if symptoms persist, keep returning, follow recent travel, or affect a young child, older adult or someone with a long-term illness.

Ask whether the timing suggests infection, food-related sensitivity or an underlying bowel condition, whether a stool test is needed, and how to replace fluids safely. Mention recent travel, medicines, sick contacts and foods eaten before symptoms began.