Diarrhoea

Diarrhoea means passing loose or watery stools more often than is normal for you.

It may come with urgency, cramping, bloating, nausea, wind or a feeling that you need the toilet again soon after going. Fluid is lost through the bowel, so thirst, a dry mouth, dizziness, darker urine or passing less urine can suggest dehydration. The pattern matters: a sudden episode differs from symptoms that return after particular foods or continue over time.

Seek urgent medical care for blood in the stool, black stools, severe or worsening abdominal pain, a swollen abdomen, repeated vomiting, confusion, fainting, or signs of significant dehydration. Get prompt advice for diarrhoea with fever, if you cannot keep fluids down, or when symptoms occur in a young child, an older adult, during pregnancy, or alongside a condition that affects immunity. Contact a clinician when it persists, keeps returning, or follows travel where an infection may need testing.

Infections, food-related reactions, bowel conditions, medicines and hormone changes can lead to diarrhoea. The linked conditions below are listed alphabetically, not by likelihood. Food poisoning, gastroenteritis, giardiasis, norovirus infection, rotavirus infection, traveller's diarrhoea and typhoid fever can involve an intestinal infection. Lactose intolerance can cause symptoms after lactose-containing foods, while irritable bowel syndrome may involve a recurring pattern with abdominal discomfort. Hyperthyroidism and ulcerative colitis are other conditions a clinician may consider from the wider symptom picture.

A clinician may ask when symptoms began, how the stool has changed, whether there is fever or pain, what you ate, recent travel, sick contacts, medicines and medical history. They may examine your abdomen and check for dehydration. A stool sample can look for infection or inflammation. Blood tests may help investigate dehydration, thyroid activity or other causes. With persistent symptoms, further bowel assessment may be considered based on the findings.

Replacing fluid and salts is a central priority while the cause is being clarified. Oral rehydration solution can be useful when losses are ongoing; follow the packet instructions and seek advice if you cannot drink enough. A clinician may recommend changes to a medicine, a temporary dietary adjustment, or treatment directed at a confirmed infection or bowel condition. Do not start antibiotics left over from an earlier illness, because the appropriate treatment depends on the cause.

Wash hands with soap after using the toilet and before preparing or eating food. Keep raw foods separate from ready-to-eat foods, cook food thoroughly, and refrigerate perishable items promptly. When travelling, choose food and water with care and carry a plan for oral rehydration. If a particular food repeatedly triggers symptoms, record the food, amount and timing rather than cutting out several food groups without guidance.

Note stool frequency and appearance, abdominal pain, fever, vomiting, weight change, rashes, joint symptoms, recent antibiotics, travel and foods eaten before symptoms. Tell a clinician about blood or mucus in the stool. A clear timeline can help separate a sudden infection from a recurring food-related or inflammatory pattern.

Diarrhoea can lead to dehydration and disruption of normal activities. When it continues or returns, it may signal an infection that has not settled, a food-related trigger, a bowel condition or another health issue requiring targeted care. Early attention to warning signs helps prevent fluid loss from becoming more serious.